Pramipexole belongs to the dopamine antagonists. The drug is used to treat Parkinson’s disease.
What is pramipexole?
Pramipexole belongs to the dopamine antagonists. The drug is used to treat Parkinson’s disease. Pramipexole is a drug from the group of dopamine antagonists. This means that the substance mimics the effect of natural dopamine. The drug is used in the treatment of Parkinson’s disease. Thus, pramipexole is considered the standard preparation for people under 70 years of age with this disease. A positive feature of pramipexole is that its use can postpone the use of the drug levodopa in the initial stages of Parkinson’s disease. This is considered an advantage because levodopa has significant side effects. Pramipexole primarily combats tremor, which is considered typical of Parkinson’s disease. Regardless of its dosage, pramipexole is always subject to prescription. In Germany, pramipexole was launched in 1997 by the drug company Boehringer. Patent protection expired in 2009, allowing several generics to enter the market with pramipexole as the active ingredient.
Pharmacologic effect
In the context of Parkinson’s disease, affected individuals suffer from the demise of nerve cells that release the neurotransmitter dopamine for reasons that are not yet fully understood. However, humans cannot do without dopamine because they need it for their movement processes. Due to the affected nerve cells (neurons) in the substantia nigra, Parkinson’s patients suffer from typical symptoms such as tremors, movement disorders and muscle rigidity. As the disease progresses, the Parkinson’s disease progresses continuously. Pramipexole, which is administered either alone or together with levodopa, is used to treat the symptoms. Pramipexole makes it possible to effectively combat patients’ tremors. In this process, the dopamine antagonist is primarily bound to D3 dopamine receptors, which are located on brain cells. The binding process results in better transmission of stimuli within the brain from neurons to each other. In this way, the patient is given the opportunity to coordinate and implement his movements more effectively. If Parkinson’s disease is still in its early stages, the effect of pramipexole is based on its influence on the control loop selfregulation. In this process, the active ingredient pretends that sufficient dopamine is present. The nerve cells therefore no longer overwork themselves by constantly producing dopamine. In the late stages of PD, most of the dopamine-secreting neurons within the substantia nigra have already died. Pramipexole then exerts its effect directly on the neurons of the striatum. It is believed that the binding of pramipexole to the D3 dopamine receptors also has a positive effect on restless legs syndrome. According to recent studies, there is also a positive effect of the drug on bipolar disorder and depression. Pramipexole is absorbed into the bloodstream of the human body via the intestine. The active ingredient reaches its maximum quantity there after one to three hours. Across the blood–brain barrier, pramipexole is passed on to the brain. No significant breakdown of the dopamine antagonist takes place within the body. About 50 percent of the drug is passed out of the body through the urine without any changes.
Medical application and use
Pramipexole is used in all stages of Parkinson’s disease. It can be administered alone or combined with levodopa. It is important that the drug be administered continuously and over an extended period of time. Another indication for pramipexole is restless legs syndrome. The drug is administered to the patient for its treatment in moderate and severe cases of the disease. Restless legs syndrome is characterized by nervous insensations in the legs. These are worse when the patient is at rest, requiring constant movement of the legs. For the treatment of restless legs syndrome, pramipexole is administered one at a time. Pramipexole is taken in the form of tablets. In the process, the patient starts with a low dose at the beginning. In the further course, the dosage increases to the optimal level. The tablets are taken three times a day. The recommended dose is 3.3 milligrams.If levodopa is used at the same time, the dose of pramipexole is lower. If retard tablets are used, only one dose per day is required, because the active ingredient can be released from these preparations throughout the day.
Risks and side effects
Taking pramipexole may be associated with bothersome side effects. Not all patients experience bothersome side effects, as each patient’s individual response varies. In most cases, affected individuals suffer from involuntary facial movements, low blood pressure, dizziness, nausea, and drowsiness. Other possible side effects include confusion, behavioral abnormalities, headache, memory problems, visual disturbances, restlessness, sleep problems, fatigue, weight loss, edema in the limbs, constipation and vomiting. Rarely, disturbances of libido, sudden falling asleep, breathing problems, skin rashes, itching, and delusions also show up. Since sleep attacks may occur as a result of taking pramipexole, driving motor vehicles and high-risk work activities are not recommended. There is a risk of interactions when pramipexole is administered at the same time as the Parkinson’s drug amatadine and the stomach preparation cimetidine. For example, these drugs hinder the excretion of the dopamine antagonist via the kidney. For this reason, a reduction in the pramipexole dosage is considered sensible. Pregnant and breastfeeding women should not take pramipexole because the effects on them and the child are not known. Other contraindications include hypersensitivity to the active ingredient and the performance of blood purification. Also of concern are serious cardiovascular disease, delusions, and psychotic disorders. If renal function is impaired, the physician must adjust the pramipexole dose accordingly.