Dopamine agonists are a group of medications that mimic the actions of the neurotransmitter dopamine. Drugs in this medication group include apomorphine, bromocriptine, cabergoline, pramipexole, ropinirole and rotigotine. Dopamine agonists are prescribed primarily for the treatment of Parkinson's disease, a progressive movement disorder caused by loss of dopamine-producing nerve cells in the brain. Due to alterations in brain and nerve chemistry, side effects prove common with dopamine agonist medications.
Edema
Edema--swelling of the soft tissues of the body--may occur with the administration of dopamine agonists. In a 2008 study published by "The Cochrane Database of Systematic Reviews," Dr. Rebecca Stowe and colleagues reported that dopamine agonists are significantly more likely to cause edema than levodopa. Levodopa is another commonly used medication for the treatment of Parkinson's disease. Once in the brain, enzymes convert levodopa into dopamine.
Drowsiness
The National Institute of Neurological Disorders and Stroke notes that dopamine agonist medications frequently cause drowsiness. The study conducted by Stowe and colleagues found drowsiness occurs more frequently with dopamine agonists than with levodopa.
Dyskinesia
Prolonged administration of dopamine agonists may lead to dyskinesia, reports the National Institute of Neurological Disorders and Stroke. Dyskinesia involves involuntary movements of the head, face and extremities. Twisting, jerking, writhing, grimacing and twitching may occur. Abnormal postures typify dyskinetic movement. In the extreme, dyskinesia leads to incessant involuntary movement. Notably, dyskinesia occurs less frequently with dopamine agonists compared to levodopa.
Nausea and Constipation
Nausea and constipation are frequent gastrointestinal side effects of dopamine agonist treatment. The analysis conducted by Stowe and colleagues found that nausea and constipation occurred more commonly with dopamine agonists compared to levodopa.
Dizziness
Information provided by MayoClinic.com notes that low blood pressure on standing may occur with dopamine agonist treatment. The drop in blood pressure often causes dizziness, which may increase the risk for falls and serious accidental injury. Stowe and colleagues concluded from their analysis that dizziness is more frequent in those taking dopamine agonists compared to those on levodopa for the treatment of Parkinson's disease.
Hallucinations
Hallucinations--hearing or seeing things that are not physically occurring--are a well-known side effect of medical treatments for Parkinson's disease. In a 2009 study published in the journal "BioMed Central Neurology," Dr. Daniel Ecker and colleagues reported that dopamine agonists are significantly more likely to cause hallucinations and other psychotic symptoms than levodopa. Use of multiple medications and the presence of other diseases along with Parkinson's disease correlated with an increased risk for psychosis among the study participants.
References
- Cleveland Clinic Center for Continuing Education: Parkinson's Disease
- National Institute of Neurological Disorders and Stroke: Parkinson's Disease, Drug Treatments
- The Cochrane Library: Dopamine Agonist Therapy in Early Parkinson's Disease
- "BioMed Central Neurology"; Dopamine Agonists and Their Risk to Induce Psychotic Episodes in Parkinson's disease: A Case-Control Study; Daniel Ecker, M.D., et al.; June 2009
- Drugs.com: Apokyn FDA Monograph
