Antiparkinsonian

Antiparkinson medication, any medication for the alleviation of the symptoms of Parkinson’s disease or other Parkinsonian conditions. The primary antiparkinson medications are levodopa, dopamine-receptor agonists, amantadine, and so-called COMT (catechol-O-methyltransferase) inhibitors, MAO-B (monoamine oxidase B) inhibitors, and muscarinic receptor antagonists.

The best treatment for Parkinson’s disease is the administration of the metabolic precursor to the neurotransmitter dopamine, levodopa (l-dopa). Levodopa penetrates the blood-brain barrier (a physiological barrier inhibiting the penetration of large molecules into the central nervous system) through special carrier proteins and is metabolized to dopamine within the brain, predominantly in the area that includes the substantia nigra. Though originally helpful in producing a dramatic remission of symptoms, levodopa often works for only 5 to 10 years, and severe side effects such as unpredictable movements, hallucinations, frequent nausea and vomiting, and alteration in behaviour and mood often follow therapy. Cotreatment with a drug named carbidopa, which blocks an enzyme responsible for degrading levodopa before it crosses the blood-brain barrier, enables higher levels of levodopa to enter the brain. Therefore, levodopa-carbidopa combination treatment allows for the administration of lower doses of levodopa with the effect of minimising side effects. Levodopa-carbidopa combination treatment has enabled a considerable number of patients to lead fairly normal lives. A medication called entacapone, which decelerates levodopa metabolism, can be administered along with levodopa and carbidopa.

Other medications to treat the symptoms of Parkinson’s disease include drugs that stimulate brain dopamine production, such as pergolide and bromocriptine, and drugs that reduce the breakdown of dopamine, including selegiline. Furthermore, the antiviral drug amantadine can alleviate some symptoms of the disease.