Definition
Cholinergic stimulants are a class of drugs that produce the same effects as those of the body's parasympathetic nervous system. Cholinergic drugs are used for a variety of purposes, including the treatment of myasthenia gravis and during anesthesia.
Purpose
The parasymapthetic nervous system is responsible for conserving and restoring energy in the body by regulating day-to-day functions such as digestion, sphincter muscle relaxation, salivation, and reducing heart rate and blood pressure. Nerve impulses in the parasympathetic nervous system are transmitted from one nerve junction to another with the help of acetylcholine, the most common neurotransmitter in the parasympathetic nervous system. Cholinergic drugs are drugs that affect the levels of acetylcholine at the nerve junction.
Cholinergic stimulants result in increased acetylcholine accumulation at the neuromuscular junction and prolong its effect. Cholinergic stimulant drugs are used in the diagnosis and treatment of myasthenia gravis, a disorder of nerve impulse transmission at the neuromuscular junction, resulting in severe muscle weakness. Cholinergic stimulants are also used in surgery to reduce urinary retention and to counteract the effects of some muscle relaxant medications given during anesthesia.
Description
Cholinergic stimulant drugs include edrophonium chloride, (brand name, Tensilon), neostigmine (Prostigmine), piridogstimina (Mestinon), and ambenonium chloride (Mytelase). Cholinergic stimulants are available in tablet, syrup, time-release tablet, and injectable forms.
Recommended dosage
Cholinergic stimulants are given in varying dosages according to the reason for use. In the treatment of myasthenia gravis, cholinergic stimulant dosages are tailored to the individual person. Patients are encouraged to keep a diary and record their response to each dose during the initial treatment period, as well as during periods of increased muscle weakness, stress, and other illness, as these conditions frequently require adjustments in dosage.
Precautions
Cholinergic stimulant drugs may not be suitable for persons with asthma, heart block or slow heart rate, epilepsy, hyperactive thyroid gland, bladder obstruction, gastrointestinal tract obstruction, or stomach ulcer. Patients should notify their physicians if they have any of these conditions before taking these drugs.
Side effects
The adverse effects of cholinergic stimulants include mostly rash and digestive system complaints, including queasiness, loose stools, nausea, vomiting, abdominal cramps, muscle pain, increased salivation, increase in stomach acid production, and diarrhea. Rare and potentially more serious side effects include reduced heart rate, possibly leading to cardiac arrest, and weak, shallow breathing.
Interactions
Certain antibiotics, especially neomycin, streptomycin, and kanamycin, can exacerbate the effects of some cholinergic stimulants. These antibiotics should be used with caution by people with myasthenia gravis.
Resources
BOOKS
Henderson, Ronald E. Attacking Myasthenia Gravis. Seattle Court Street Press, 2002.
Staff. The Official Patient's Sourcebook on Myasthenia Gravis: A Revised and Updated Directory for the Internet Age. San Diego: Icon Health Publications Group Int., 2002.
OTHER
"Myasthenia Gravis Fact Sheet." National Institute of Neurological Disorders and Stroke. February 11, 2004 (May 22, 2004). http://www.ninds.nih.gov/health_and_medical/pubs/myasthenia_gravis.htm.
"Tensilon Test." Medline Plus. National Library of Medicine. May 14, 2004 (May 22, 2004). http://www.nlm.nih.gov/medlineplus/ency/article/003930.htm.
ORGANIZATIONS
Myasthenia Gravis Foundation of America, Inc. 5841 Cedar Lake Road Suite 204, Minneapolis, MN 55416. (952) 545-9438 or (800) 541-5454; Fax: (952) 646-2028. myastheniagravis@msn.com. http://www.myasthenia.org.
Adrienne Wilmoth Lerner
