Route of administration
Encyclopedia
A route of administration in pharmacology
and toxicology
is the path by which a drug
, fluid, poison, or other substance is taken into the body.
(concerning the processes of uptake, distribution, and elimination of drugs). Nevertheless, some routes, especially the transdermal
or transmucosal routes, are commonly referred to routes of administration. The location of the target effect of active substances are usually rather a matter of pharmacodynamics
(concerning e.g. the physiological effects of drugs). Furthermore, there is also a classification of routes of administration that basically distinguishes whether the effect is local (in "topical" administration) or systemic (in "enteral" or "parenteral" administration).
is sometimes termed enteral or enteric administration (strictly meaning 'through the intestines'). Enteral/enteric administration usually includes oral
(through the mouth
) and rectal (into the rectum
) administration, in the sense that these are taken up by the intestines. However, uptake of drugs administered orally may also occur already in the stomach
, why gastrointestinal (along the gastrointestinal tract
) may be a more fitting word for this route of administration. Furthermore, some application locations often classified as enteral, such as sublingual (under the tongue) and sublabial
or buccal (between the cheek and gums/gingiva
), are taken up in the proximal part of the gastrointestinal tract without reaching the intestines. Strictly enteral administration (directly into the intestines) can be used for systemic administration, as well as local (sometimes termed topical
), such as in enema
where e.g. contrast media is infused into the intestines for imaging. However, in the classification system basically distinguishing substances by location of their effects, the term enteral is reserved for substances with systemic effects.
Many drugs as tablet
s, capsules, or drops are taken orally. Administration methods directly into the stomach include those by gastric feeding tube or gastrostomy
. Substances may also be placed into the small intestine
s, as with a duodenal feeding tube and enteral nutrition.Some enteric coated tablets will not dissolve in stomach but it is directed to the intestine because the drug present in the enteric coated tablet causes irritation in the stomach.
(concerning the processes of uptake, distribution, and elimination of drugs). Nevertheless, the following routes are commonly referred to as routes of administration:
and has systemic
effects:
Disadvantages
Advantages
Disadvantages
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
and toxicology
Toxicology
Toxicology is a branch of biology, chemistry, and medicine concerned with the study of the adverse effects of chemicals on living organisms...
is the path by which a drug
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
, fluid, poison, or other substance is taken into the body.
Classification
Routes of administration are usually classified by application location (or exposition). The route or course the active substance takes from application location to the location where it has its target effect is usually rather a matter of pharmacokineticsPharmacokinetics
Pharmacokinetics, sometimes abbreviated as PK, is a branch of pharmacology dedicated to the determination of the fate of substances administered externally to a living organism...
(concerning the processes of uptake, distribution, and elimination of drugs). Nevertheless, some routes, especially the transdermal
Transdermal
Transdermal is a route of administration wherein active ingredients are delivered across the skin for systemic distribution. Examples include transdermal patches used for medicine delivery, and transdermal implants used for medical or aesthetic purposes....
or transmucosal routes, are commonly referred to routes of administration. The location of the target effect of active substances are usually rather a matter of pharmacodynamics
Pharmacodynamics
Pharmacodynamics is the study of the biochemical and physiological effects of drugs on the body or on microorganisms or parasites within or on the body and the mechanisms of drug action and the relationship between drug concentration and effect...
(concerning e.g. the physiological effects of drugs). Furthermore, there is also a classification of routes of administration that basically distinguishes whether the effect is local (in "topical" administration) or systemic (in "enteral" or "parenteral" administration).
Gastrointestinal/enteral
Administration through the gastrointestinal tractGastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
is sometimes termed enteral or enteric administration (strictly meaning 'through the intestines'). Enteral/enteric administration usually includes oral
Oral administration
Oral administration is a route of administration where a substance is taken through the mouth.-Terminology:Per os is an adverbial phrase meaning literally from Latin "by mouth" or "by way of the mouth." The expression is used in medicine to describe a treatment that is taken orally. The...
(through the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
) and rectal (into the rectum
Rectum
The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
) administration, in the sense that these are taken up by the intestines. However, uptake of drugs administered orally may also occur already in the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
, why gastrointestinal (along the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
) may be a more fitting word for this route of administration. Furthermore, some application locations often classified as enteral, such as sublingual (under the tongue) and sublabial
Sublabial administration
Sublabial, literally 'under the lip', from Latin, refers to the pharmacological route of administration by which the active substance is placed between the lip and the gingiva....
or buccal (between the cheek and gums/gingiva
Gingiva
The gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...
), are taken up in the proximal part of the gastrointestinal tract without reaching the intestines. Strictly enteral administration (directly into the intestines) can be used for systemic administration, as well as local (sometimes termed topical
Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
), such as in enema
Enema
An enema is the procedure of introducing liquids into the rectum and colon via the anus. The increasing volume of the liquid causes rapid expansion of the lower intestinal tract, often resulting in very uncomfortable bloating, cramping, powerful peristalsis, a feeling of extreme urgency and...
where e.g. contrast media is infused into the intestines for imaging. However, in the classification system basically distinguishing substances by location of their effects, the term enteral is reserved for substances with systemic effects.
Many drugs as tablet
Tablet
A tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose...
s, capsules, or drops are taken orally. Administration methods directly into the stomach include those by gastric feeding tube or gastrostomy
Gastrostomy
Gastrostomy refers to a surgical opening into the stomach. Creation of an artificial external opening into the stomach for nutritional support or gastrointestinal compression....
. Substances may also be placed into the small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
s, as with a duodenal feeding tube and enteral nutrition.Some enteric coated tablets will not dissolve in stomach but it is directed to the intestine because the drug present in the enteric coated tablet causes irritation in the stomach.
Central nervous system
- epiduralEpiduralThe term epidural is often short for epidural analgesia, a form of regional analgesia involving injection of drugs through a catheter placed into the epidural space...
(synonym: peridural) (injection or infusion into the epidural spaceEpidural spaceIn the spine, the epidural space is the outermost part of the spinal canal. It is the space within the canal lying outside the dura mater...
), e.g. epidural anesthesia - intracerebral (into the cerebrum) direct injection into the brain. Used in experimental research of chemicals and as a treatment for malignancies of the brain. The intracerebral route can also interrupt the blood brain barrier from holding up against subsequent routes.
- intracerebroventricular (into the cerebral ventricles) administration into the ventricular system of the brain. One use is as a last line of opioid treatment for terminal cancer patients with intractable cancer painCancer painPain is a symptom frequently associated with cancer. Cancer can cause pain by irritating or damaging nerves, by stimulating nociceptors , or by releasing chemicals that make nociceptors respond to normally non-painful stimuli. Cancer pain may be caused by the tumor itself or by medical...
.
Other locations
- epicutaneous (application onto the skin). It can be used both for local effect as in allergy testing and typical local anesthesiaLocal anesthesiaLocal anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...
, as well as systemicSystemicSystemic refers to something that is spread throughout, system-wide, affecting a group or system such as a body, economy, market or society as a whole. Systemic may also refer to:-In medicine:...
effects when the active substance diffuses through skin in a transdermalTransdermalTransdermal is a route of administration wherein active ingredients are delivered across the skin for systemic distribution. Examples include transdermal patches used for medicine delivery, and transdermal implants used for medical or aesthetic purposes....
route. - intradermal, (into the skin itself) is used for skin testing some allergens, and also for mantoux testMantoux testThe Mantoux test is a diagnostic tool for tuberculosis. It is one of the two major tuberculin skin tests used in the world, largely replacing multiple-puncture tests such as the Tine test...
for Tuberculosis - subcutaneous (under the skin), e.g. insulinInsulinInsulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
. Skin poppingSkin poppingSkin popping is a method of administration for the use of drugs by injecting or placing the substance or drug under the skin. It can include subcutaneous placement or intradermal placement though is also rarely used to mean intramuscular injection. It is however as a term distinct from the meaning...
is a slang term that includes this method of administration, and is usually used in association with recreational drugs. - nasalHuman noseThe visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
administration (through the nose) can be used for topically acting substances, as well as for insufflationInsufflation (medicine)Insufflation is the practice of inhaling a substance. Insufflation has limited medical use, but is a common route of administration with many respiratory drugs used to treat conditions in the lungs and paranasal sinus .The technique is common for many recreational drugs and is also used for some...
of e.g. decongestantDecongestantA decongestant or nasal decongestant is a type of drug that is used to relieve nasal congestion.-Pharmacology:The vast majority of decongestants act via enhancing norepinephrine and epinephrine or adrenergic activity by stimulating the α-adrenergic receptors...
nasal sprays to be taken up along the respiratory tractRespiratory tractIn humans the respiratory tract is the part of the anatomy involved with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
. Such substances are also called inhalational, e.g. inhalational anesthetics. - intravenousIntravenous therapyIntravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...
(into a veinVeinIn the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
), e.g. many drugs, total parenteral nutrition - intraarterial (into an arteryArteryArteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
), e.g. vasodilator drugs in the treatment of vasospasmVasospasmVasospasm refers to a condition in which blood vessels spasm, leading to vasoconstriction. This can lead to tissue ischemia and death . Cerebral vasospasm may arise in the context of subarachnoid hemorrhage. Symptomatic vasospasm or delayed cerebral ischemia is a major contributor to...
and thrombolytic drugThrombolytic drugThrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. They limit the damage caused by the blockage of the blood vessel.-Uses:...
s for treatment of embolismEmbolismIn medicine, an embolism is the event of lodging of an embolus into a narrow capillary vessel of an arterial bed which causes a blockage in a distant part of the body.Embolization is... - intramuscularIntramuscular injectionIntramuscular injection is the injection of a substance directly into a muscle. In medicine, it is one of several alternative methods for the administration of medications . It is used for particular forms of medication that are administered in small amounts...
(into a muscleMuscleMuscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
), e.g. many vaccineVaccineA vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s, antibiotics, and long-term psychoactive agents. Recreationally the colloquial term 'muscling' is used. - intracardiac (into the heart), e.g. adrenaline during cardiopulmonary resuscitationCardiopulmonary resuscitationCardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...
(no longer commonly performed) - intraosseous infusionIntraosseous infusionIntraosseous infusion is the process of injection directly into the marrow of a bone. This technique is used in emergency situations to provide fluids and medication when intravenous access is not available or not feasible.-History:...
(into the boneBoneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
marrow) is, in effect, an indirect intravenous access because the bone marrow drains directly into the venous system. This route is occasionally used for drugs and fluids in emergency medicine and pediatrics when intravenous access is difficult. - intrathecalIntrathecalIntrathecal is an adjective that refers to something introduced into or occurring in the space under the arachnoid membrane of the brain or spinal cord...
(into the spinal canal) is most commonly used for spinal anesthesiaAnesthesiaAnesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
and chemotherapyChemotherapyChemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen.... - intraperitonealIntraperitoneal injectionIntraperitoneal injection or IP injection is the injection of a substance into the peritoneum . IP injection is more often applied to animals than humans...
, (infusion or injection into the peritoneumPeritoneumThe peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom — it covers most of the intra-abdominal organs — in amniotes and some invertebrates...
) e.g. peritoneal dialysisPeritoneal dialysisPeritoneal dialysis is a treatment for patients with severe chronic kidney disease. The process uses the patient's peritoneum in the abdomen as a membrane across which fluids and dissolved substances are exchanged from the blood... - IntravesicalUrinary bladderThe urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
infusion is into the urinary bladder. - intravitreal, through the eye
- Intracavernous injection, an injection into the base of the penisPenisThe penis is a biological feature of male animals including both vertebrates and invertebrates...
- Intravaginal administrationIntravaginal administrationIntravaginal administration is a route of administration where the substance is applicated inside the vagina. Pharmacologically, it has the potential advantage to result in effects primarily in the vagina or nearby structures with limited systemic adverse effects compared to other routes of...
, in the vaginaVaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the... - Intrauterine
- Extra-amniotic administrationExtra-amniotic administrationExtra-amniotic administration is a route of administration to the space between the fetal membranes and endometrium inside the uterus of a pregnant woman.It can be used to administer drugs affecting uterus motility, such as oxytocin and prostaglandins, e.g...
, between the endometriumEndometrium-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
and fetal membranesFetal membranesThe fetal membranes, or chorioamniotic membranes, are the amnion and chorion which surround and protect a developing fetus....
- Extra-amniotic administration
Route from application to target
The route or course the active substance takes from application location to the location where it has its target effect is usually rather a matter of pharmacokineticsPharmacokinetics
Pharmacokinetics, sometimes abbreviated as PK, is a branch of pharmacology dedicated to the determination of the fate of substances administered externally to a living organism...
(concerning the processes of uptake, distribution, and elimination of drugs). Nevertheless, the following routes are commonly referred to as routes of administration:
- transdermal (diffusion through the intact skin for systemic rather than topical distribution), e.g. transdermal patchTransdermal patchA transdermal patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream. Often, this promotes healing to an injured area of the body. An advantage of a transdermal drug delivery route over other types of...
es such as fentanyl in pain therapy, nicotineNicotineNicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...
patches for treatment of addictionSubstance use disorderSubstance use disorders include substance abuse and substance dependence. In DSM-IV, the conditions are formally diagnosed as one or the other, but it has been proposed that DSM-5 combine the two into a single condition called "Substance-use disorder"....
and nitroglycerine for treatment of angina pectoris. - transmucosal (diffusion through a mucous membrane), e.g. insufflationInsufflation (medicine)Insufflation is the practice of inhaling a substance. Insufflation has limited medical use, but is a common route of administration with many respiratory drugs used to treat conditions in the lungs and paranasal sinus .The technique is common for many recreational drugs and is also used for some...
(snorting) of cocaineCocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
, sublingualSublingualSublingual, literally 'under the tongue', from Latin, refers to the pharmacological route of administration by which drugs diffuse into the blood through tissues under the tongue...
, i.e. under the tongue, sublabial, i.e. between the lips and gingivaGingivaThe gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...
, nitroglycerine, vaginal suppositories
Local or systemic effect
Routes of administration can also basically be classified whether the effect is local (in topical administration) or systemic (in enteral or parenteral administration):- topicalTopicalIn medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
: local effect, substance is applied directly where its action is desired. Sometimes, however, the term topical is defined as applied to a localized area of the body or to the surface of a body part, without necessarily involving target effect of the substance, making the classification rather a variant of the classification based on application location. - enteralEnteralIn pharmacology, Enteral is a term used to describe routes of drug administration that involve absorption of the drug through the gastrointestinal tract. The term may also be used to describe something as residing in the gastrointestinal tract...
: desired effect is systemic (non-local), substance is given via the digestive tract. - parenteralParenteralParenteral is a route of administration that involves piercing the skin or mucous membrane. Parenteral nutrition refers to providing nutrition via the veins.-Etymology:...
: desired effect is systemic, substance is given by routes other than the digestive tract.
Topical
- epicutaneous (application onto the skin), e.g. allergy testing, typical local anesthesiaLocal anesthesiaLocal anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...
- inhalational, e.g. asthmaAsthmaAsthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
medications - enemaEnemaAn enema is the procedure of introducing liquids into the rectum and colon via the anus. The increasing volume of the liquid causes rapid expansion of the lower intestinal tract, often resulting in very uncomfortable bloating, cramping, powerful peristalsis, a feeling of extreme urgency and...
, e.g. contrast media for imaging of the bowel - eye drops (onto the conjunctivaConjunctivaThe conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
), e.g. antibioticAntibioticAn antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s for conjunctivitis - ear drops - such as antibiotics and corticosteroids for otitis externaOtitis externaOtitis externa is an inflammation of the outer ear and ear canal. Along with otitis media, external otitis is one of the two human conditions commonly called "earache". It also occurs in many other species. Inflammation of the skin of the ear canal is the essence of this disorder...
- through mucous membranes in the body
Enteral
In this classification system, enteral administration is administration that involves any part of the gastrointestinal tractGastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
and has systemic
Systemic
Systemic refers to something that is spread throughout, system-wide, affecting a group or system such as a body, economy, market or society as a whole. Systemic may also refer to:-In medicine:...
effects:
- by mouthMouthThe mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
(orally), many drugs as tabletTabletA tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose...
s, capsules, or drops - by gastric feeding tube, duodenal feeding tube, or gastrostomyGastrostomyGastrostomy refers to a surgical opening into the stomach. Creation of an artificial external opening into the stomach for nutritional support or gastrointestinal compression....
, many drugs and enteral nutrition - rectallyRectumThe rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
, various drugs in suppositorySuppositoryA suppository is a drug delivery system that is inserted into the rectum , vagina or urethra , where it dissolves.They are used to deliver both systemically-acting and locally-acting medications....
Parenteral
- intravenousIntravenous therapyIntravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...
(into a veinVeinIn the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
), e.g. many drugs, total parenteral nutrition - intra-arterial (into an arteryArteryArteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
), e.g. vasodilator drugs in the treatment of vasospasmVasospasmVasospasm refers to a condition in which blood vessels spasm, leading to vasoconstriction. This can lead to tissue ischemia and death . Cerebral vasospasm may arise in the context of subarachnoid hemorrhage. Symptomatic vasospasm or delayed cerebral ischemia is a major contributor to...
and thrombolytic drugThrombolytic drugThrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. They limit the damage caused by the blockage of the blood vessel.-Uses:...
s for treatment of embolismEmbolismIn medicine, an embolism is the event of lodging of an embolus into a narrow capillary vessel of an arterial bed which causes a blockage in a distant part of the body.Embolization is... - intraosseous infusionIntraosseous infusionIntraosseous infusion is the process of injection directly into the marrow of a bone. This technique is used in emergency situations to provide fluids and medication when intravenous access is not available or not feasible.-History:...
(into the boneBoneBones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
marrow) is, in effect, an indirect intravenous access because the bone marrow drains directly into the venous system. This route is occasionally used for drugs and fluids in emergency medicine and pediatrics when intravenous access is difficult. - intra-muscular
- intracerebral (into the brain parenchymaParenchymaParenchyma is a term used to describe a bulk of a substance. It is used in different ways in animals and in plants.The term is New Latin, f. Greek παρέγχυμα - parenkhuma, "visceral flesh", f. παρεγχεῖν - parenkhein, "to pour in" f. para-, "beside" + en-, "in" + khein, "to pour"...
) - intracerebroventricular (into cerebral ventricular system)
- subcutaneous (under the skin)
Advantages and disadvantages
There are advantages and disadvantages to each route of administrationInhalation
Advantages- Fastest method, 7–10 seconds for the drug to reach the brain
- User can titrate (regulate the amount of drug they are receiving)
Disadvantages
- Typically a more addictive route of administration because it is the fastest, leading to instant gratification. In addition, drugs taken by inhalation do not stay in the bloodstream for as long, causing the user to redose more quickly and intensifying the association between consuming the drug and its effects.
- Difficulties in regulating the exact amount of dosage
- Patient having difficulties administering a drug via inhaler
Injection
Injection encompasses intravenous (IV), intramuscular (IM), and subcutaneous (subcut)Advantages
- Fast: 15–30 seconds for IV, 3–5 minutes for IM and subcutaneous (subcut)
- 100% bioavailability
- suitable for drugs not absorbed by the gut or those that are too irritant (anti-cancer)
- One injection can be formulated to last days or even months, e.g., Depo-Provera, a birth control shot that works for three months
- IV can deliver continuous medication, e.g., morphineMorphineMorphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
for patients in continuous pain, or salineSaline (medicine)In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...
drip for people needing fluids
Disadvantages
- Onset of action is quick, hence more risk of addiction when it comes to injecting drugs of abuse
- Patients are not typically able to self-administer
- Belonephobia, the fear of needles and injection.
- If needles are shared, there is risk of HIVHIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
and other infectious diseases - It is the most dangerous route of administration because it bypasses most of the body's natural defenses, exposing the user to health problems such as hepatitisHepatitisHepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
, abscessAbscessAn abscess is a collection of pus that has accumulated in a cavity formed by the tissue in which the pus resides due to an infectious process or other foreign materials...
es, infections, and undissolved particles or additives/contaminants - If not done properly, potentially fatal air bolusesBolus (medicine)In medicine, a bolus is the administration of a medication, drug or other compound that is given to raise its concentration in blood to an effective level...
(bubbles) can occur. - Need for strict asepsisAsepsisAsepsis is the state of being free from disease-causing contaminants or, preventing contact with microorganisms. The term asepsis often refers to those practices used to promote or induce asepsis in an operative field in surgery or medicine to prevent infection...
Uses
- Some routes can be used for topical as well as systemic purposes, depending on the circumstances. For example, inhalation of asthma drugs is targeted at the airways (topical effect), whereas inhalation of volatile anestheticsGeneral anaestheticA general anaesthetic is a drug that brings about a reversible loss of consciousness. These drugs are generally administered by an anaesthesia provider to induce or maintain general anaesthesia to facilitate surgery...
is targeted at the brain (systemic effect).
- On the other hand, identical drugs can produce different results depending on the route of administration. For example, some drugs are not significantly absorbed into the bloodstream from the gastrointestinal tract and their action after enteral administration is therefore different from that after parenteral administration. This can be illustrated by the action of naloxoneNaloxoneNaloxone is an opioid antagonist drug developed by Sankyo in the 1960s. Naloxone is a drug used to counter the effects of opiate overdose, for example heroin or morphine overdose. Naloxone is specifically used to counteract life-threatening depression of the central nervous system and respiratory...
(Narcan), an antagonist of opiateOpiateIn medicine, the term opiate describes any of the narcotic opioid alkaloids found as natural products in the opium poppy plant.-Overview:Opiates are so named because they are constituents or derivatives of constituents found in opium, which is processed from the latex sap of the opium poppy,...
s such as morphineMorphineMorphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
. Naloxone counteracts opiate action in the central nervous systemCentral nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
when given intravenously and is therefore used in the treatment of opiate overdose. The same drug, when swallowed, acts exclusively on the bowels; it is here used to treat constipation under opiate pain therapy and does not affect the pain-reducing effect of the opiate.
- Enteral routes are generally the most convenient for the patient, as no punctures or sterile procedures are necessary. Enteral medications are therefore often preferred in the treatment of chronic disease. However, some drugs can not be used enterally because their absorption in the digestive tract is low or unpredictable. Transdermal administration is a comfortable alternative; there are, however, only a few drug preparations that are suitable for transdermal administration.
- In acute situations, in emergency medicineEmergency medicineEmergency medicine is a medical specialty in which physicians care for patients with acute illnesses or injuries which require immediate medical attention. While not usually providing long-term or continuing care, emergency medicine physicians diagnose a variety of illnesses and undertake acute...
and intensive care medicineIntensive care medicineIntensive-care medicine or critical-care medicine is a branch of medicine concerned with the diagnosis and management of life threatening conditions requiring sophisticated organ support and invasive monitoring.- Overview :...
, drugs are most often given intravenously. This is the most reliable route, as in acutely ill patients the absorption of substances from the tissues and from the digestive tract can often be unpredictable due to altered blood flow or bowel motility.
See also
- ADMEADMEADME is an acronym in pharmacokinetics and pharmacology for absorption, distribution, metabolism, and excretion, and describes the disposition of a pharmaceutical compound within an organism...
- CatheterCatheterIn medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
- Dosage formDosage form-Introduction:Dosage forms are a mixture of active drug components and nondrug components. Depending on the method of administration they come in several types. These are liquid dosage form, solid dosage form and semisolid dosage forms. A Liquid dosage form is the liquid form of a dose of a...
- Drug injectionDrug injectionIn substance dependence and recreational drug use, drug injection is a method of introducing a drug into the body with a hollow needle and a syringe which is pierced through the skin into the body...
- Hypodermic needleHypodermic needleA hypodermic needle is a hollow needle commonly used with a syringe to inject substances into the body or extract fluids from it...
- Medical injectionInjection (medicine)An injection is an infusion method of putting fluid into the body, usually with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body...
- Intravenous Marijuana SyndromeIntravenous Marijuana SyndromeIntravenous Marijuana Syndrome is a rare distinct short-term clinical syndrome related to the IV injection of boiled cannabis broth, which had been filtered through a cotton cloth. The syndrome has at least 25 known cases in the English language literature, all prior to 1983...
- List of medical inhalants