Ask The Pharmacist

DRUGS FOR PARKINSON’S DISEASE QUESTION: What drugs are used to treat Parkinson’s disease? ANSWER: Parkinson’s disease (PD) is a slowly progressive brain disorder in which various cells (neurons) within the brain die or become impaired, causing a wide variety of symptoms. Movement problems are common in people with PD, including shaking or tremor, muscle stiffness and rigidity, slow movement, and walking or postural changes. Other movement or muscle related symptoms can include small, cramped handwriting, stiff facial expression, muffled speech, swallowing problems, lack of arm swing, and diminished manual dexterity. In the past, these movement problems received the most attention and numerous medications have been developed to treat them. More recently, however, PD has been redefined to include a number of other non-movement disorders that can occur, such as pain, sleep disturbances, constipation, depression, anxiety and panic disorder, psychosis, and dementia. In fact, symptoms such as constipation, loss of smell, or sleep disorders may actually occur years before the movement problems begin. One interesting thing about PD is that no two patients’ symptoms are exactly the same. For example, some patients may have tremor or shaking, while others do not. While it is beyond the scope of this column to discuss the treatment of all the potential problems associated with PD, I will briefly review the drugs used to treat the movement disorders part of the disease. Movement problems in PD are primarily due to the loss of a chemical in the brain known as dopamine. About 60-80% of the brain cells that make dopamine need to be lost or damaged before movement problems start. Drugs to replace dopamine, such as levodopa/carbidopa (Sinemet), are often used. In addition, drugs that prevent the breakdown (metabolism) of levodopa in order to increase brain concentrations of dopamine may be used, such as rasagiline (Azilect), selegiline (Zydis), tolcapone (Tasmar), or Entacapone (Comtan). Two other popular medications, ropinirole (Requip) or pramipexole (Mirapex), which “mimic” the action of dopamine in the brain may also be used. Amantadine is another unique medication that may be helpful for many patients with PD. Furthermore, older drugs known as anticholinergics (benztropine or trihexyphenidyl) may be beneficial for some younger patients with tremor. Neuroprotective medications to stop or low the progression of PD are also being studied with hopes that PD can be better treated in the future. In summary, PD is now considered a multi-system brain disorder with many movement and non-movement symptoms. Numerous medications are available to treat these problems, but much more research is needed to better understand and hopefully cure or slow down this terrible disease process. MIRAPEX QUESTION: What can you tell me about Mirapex? ANSWER: Mirapex (generic name pramipexole) is known as a dopamine receptor agonist and is used to treat Parkinson’s disease. Parkinson’s disease is an illness that causes a reduction in the amount of a chemical known as dopamine produced in the brain. This chemical helps the body to function normally, and the loss of dopamine causes physical symptoms such as rigidity, tremors, slowed movement, a shuffled walk and postural instability. Mirapex is believed to work by going to dopamine receptors in the brain and stimulating them to work, causing an improvement in symptoms. Patients taking the drug can function better in their daily living activities and also show improvements in their movements. Mirapex can be used by itself or in combination with other drugs to treat early Parkinson’s disease. It is also useful in treating patients with advanced Parkinson’s disease who are also taking levodopa, a commonly used anti-Parkinson’s drug. Some patients with advanced disease may also be able to reduce their dose of levodopa when taking Mirapex. The most common side effects reported by patients taking Mirapex during clinical trials were nausea, dizziness, drowsiness, inability to sleep, a decrease in blood pressure when rising up, movement disorders, constipation, weakness, and hallucinations. The decrease in blood pressure (fainting) when rising up is known as postural hypotension and this may occur more frequently during the initial treatment period with Mirapex. Please note that when Mirapex therapy is initiated for treating Parkinson’s disease, the dosage must be gradually increased over a number of weeks to avoid side effects. If you have any questions about your dosage schedule, please talk to your doctor and/or pharmacist. PLEASE NOTE: A generic version of Mirapex (pramipexole) and a once-daily tablet (Mirapex ER) were approved in 2010.