The drug piribedil belongs to the group of dopamine agonists and is used to treat Parkinson’s disease, with therapy aimed at alleviating the symptoms of the disease and halting further progression.
What is piribedil?
The drug piribedil belongs to the dopamine agonist group and is used to treat Parkinson’s disease. Piribedil has been used since the 1970s, when it was first used in ophthalmology and then for Parkinson’s disease. It has also been used to treat vascular disease and mild cognitive impairment. In Germany, piribedil has been on the market since 2007 and is used here for the treatment of Parkinson’s disease. Both monotherapy and combination therapy with levodopa are possible. Piribedil is primarily intended to improve patients’ mobility.
Pharmacologic action
In Parkinson’s disease, patients suffer from a lack of dopamine, a neurotransmitter that plays an essential role in the execution of movements. As a result, affected individuals suffer from tremor (shaking), rigor (muscle rigidity), and akinesia (impaired movement). To alleviate the symptoms and slow down the progression of the disease, patients receive dopamine in the form of L-dopa. However, this is converted to metabolites by different enzymes, so that inhibition of the enzymes is necessary. In addition, stimulation of the dopamine receptors (D2) must also take place by means of agonists. One such agonist is piribedil. The drug can cross the blood–brain barrier and then subsequently bind to the binding sites for dopamine. There, the drug can trigger the same reactions as dopamine. Piribedil is used primarily in the early or advanced stages of Parkinson’s disease. To some extent, piribedil also acts as an antagonist of acetylcholine.
Medical use and application
Piribedil is used to treat Parkinson’s disease. The drug is used either in combination with levodopa or alone. In the case of combination treatment, both drugs are given together from the beginning, or piribedil is added some time later. Piribedil can be absorbed and distributed very quickly in the gastrointestinal tract. Since the drug binds only moderately to plasma proteins, the interactions that can occur due to protein binding are relatively minor. The drug is preferentially administered to younger patients, with therapy aimed at delaying motor complications, such as effect fluctuations or dyskinesias. Typically, 3 to 5 tablets (150mg to 250mg) per day are taken for Parkinson’s disease therapy. These are swallowed whole with a little water after meals. If the drug is suddenly discontinued, malignant neuroleptic syndrome may occur under certain circumstances. For this reason, the dose should be reduced slowly when the drug is stopped.
Risks and side effects
In general, piribedil has very few side effects. However, if they do occur, they depend on the dose administered. If treatment is discontinued, the side effects also disappear. Piribedil should not be used in case of: cardiovascular shock, hypersensitivity to the drug, and acute myocardial infarction. In addition, Piribedil should not be taken in combination with neuroleptics as it may increase psychotic disorders. It is also not recommended to be taken during breastfeeding or pregnancy. Side effects usually occur only at the beginning of treatment. These include:
- Gastrointestinal complaints such as flatulence, vomiting or nausea.
- Dizziness, absentmindedness or hallucinations.
- Low blood pressure
- Psychiatric disorders such as hypersexuality or libido increase
- Allergic reactions
- Nausea in case of overdoses
Gastrointestinal symptoms can be reduced if the dose is gradually increased at the beginning of treatment. In addition, drowsiness may occur during therapy with piribedil, and very rarely sudden sleep attacks occur. Therefore, patients should not drive a vehicle or engage in activities that could injure them or others as well. Overdose is unlikely to occur when taking Piribedil.If this does occur, the following symptoms will occur: unstable blood pressure (hypotension or hypertension) and/or gastrointestinal symptoms (vomiting, nausea).
