Intrathecal
Encyclopedia
Intrathecal is an adjective that refers to something introduced into or occurring in the space under the arachnoid membrane of the brain
or spinal cord
. For example, intrathecal immunoglobulin production means production of this substance in the spinal cord.
As other example, an intrathecal injection (often simply called "intrathecal") is an injection
into the spinal canal (intrathecal space surrounding the spinal cord), as in a spinal anaesthesia
or in chemotherapy
or pain management
applications. This route is also used for some infections, particularly post-neurosurgical. The drug needs to be given this way to avoid the blood brain barrier. The same drug given orally must enter the blood stream and has a much harder time reaching the brain; by the time it does, most of the drug has been absorbed by the body's system and is excreted. Drugs given intrathecally often have to be made up specially by a pharmacist or technician because they cannot contain any preservative or other potentially harmful inactive ingredients that are sometimes found in standard injectable drug preparations.
cerebral palsy
, intrathecally-administered baclofen
is done through an intrathecal pump
implanted just below the skin of the stomach with a tube connected directly to the base of the spine, where it bathes the appropriate nerves using a dose about one thousand times smaller than that required by orally-administered baclofen. Intrathecal baclofen also carries none of the side effects, such as sleepiness, that typically occur with oral baclofen. However, intrathecal baclofen pumps carry serious clinical risks, such as infection or a possibly fatal sudden malfunction, that oral baclofen does not.
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
or spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. For example, intrathecal immunoglobulin production means production of this substance in the spinal cord.
As other example, an intrathecal injection (often simply called "intrathecal") is an injection
Injection (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...
into the spinal canal (intrathecal space surrounding the spinal cord), as in a spinal anaesthesia
Spinal anaesthesia
Spinal anaesthesia , also called spinal analgesia or sub-arachnoid block , is a form of regional anaesthesia involving injection of a local anaesthetic into the subarachnoid space, generally through a fine needle, usually 9 cm long...
or in chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
or pain management
Pain management
Pain management is a branch of medicine employing an interdisciplinary approach for easing the suffering and improving the quality of life of those living with pain. The typical pain management team includes medical practitioners, clinical psychologists, physiotherapists, occupational therapists,...
applications. This route is also used for some infections, particularly post-neurosurgical. The drug needs to be given this way to avoid the blood brain barrier. The same drug given orally must enter the blood stream and has a much harder time reaching the brain; by the time it does, most of the drug has been absorbed by the body's system and is excreted. Drugs given intrathecally often have to be made up specially by a pharmacist or technician because they cannot contain any preservative or other potentially harmful inactive ingredients that are sometimes found in standard injectable drug preparations.
Intrathecal administration of analgesia
- Very popular for a single 24-hour dose of analgesia (opioid with Local anesthetic)
- Caution because of late onset respiratory depression
- Severe pruritusItchItch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response...
and urinary retention may limit the use of intrathecal morphine - PethidinePethidinePethidine or meperidine Pethidine (INN) or meperidine (USAN) Pethidine (INN) or meperidine (USAN) (commonly referred to as Demerol but also referred to as: isonipecaine; lidol; pethanol; piridosal; Algil; Alodan; Centralgin; Dispadol; Dolantin; Mialgin (in Indonesia); Petidin Dolargan (in Poland);...
has the unusual properties of being both a local anaesthetic and opioid analgesicAnalgesicAn analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
which occasionally permits its use as the sole intrathecal anaesthetic agent.
Intrathecal chemotherapy
- Currently, only three agents are licensed for intrathecal chemotherapy
- They are methotrexateMethotrexateMethotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...
, cytarabineCytarabineCytarabine, or cytosine arabinoside, is a chemotherapy agent used mainly in the treatment of cancers of white blood cells such as acute myeloid leukemia and non-Hodgkin lymphoma. It is also known as Ara-C...
(a.k.a. Ara-C) and hydrocortisone
- They are methotrexate
- Administration of other chemotherapeutic agents such as vincristineVincristineVincristine , formally known as leurocristine, sometimes abbreviated "VCR", is a vinca alkaloid from the Catharanthus roseus , formerly Vinca rosea and hence its name. It is a mitotic inhibitor, and is used in cancer chemotherapy.-Mechanism:Tubulin is a structural protein that polymerizes to...
via the intrathecal route can lead to fatal outcomes.
Intrathecal baclofen
Often reserved for spasticSpastic
The word spastic is used differently depending on location which has led to some controversy and misunderstanding. Derived via Latin from the Greek spastikos , the word originally referred to a change in muscles affected by the medical condition spasticity, which is seen in spastic diplegia and...
cerebral palsy
Cerebral palsy
Cerebral palsy is an umbrella term encompassing a group of non-progressive, non-contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement....
, intrathecally-administered baclofen
Baclofen
Baclofen is a derivative of gamma-aminobutyric acid . It is primarily used to treat spasticity and is under investigation for the treatment of alcoholism....
is done through an intrathecal pump
Intrathecal pump
An intrathecal pump is a medical device used to deliver very small quantities of medications directly to the spinal fluid of a human being. Medications such as baclofen, morphine, or ziconotide may be delivered in this manner to minimize the side effects often associated with the higher dosages...
implanted just below the skin of the stomach with a tube connected directly to the base of the spine, where it bathes the appropriate nerves using a dose about one thousand times smaller than that required by orally-administered baclofen. Intrathecal baclofen also carries none of the side effects, such as sleepiness, that typically occur with oral baclofen. However, intrathecal baclofen pumps carry serious clinical risks, such as infection or a possibly fatal sudden malfunction, that oral baclofen does not.