Mirapex

Mirapex is a Boehringer Ingelheim brand of pramipexole, a medicine that stimulates dopamine receptors in the brain. In Parkinson's disease the cells that make dopamine are gradually lost, and pramipexole partly stands in for the missing messenger, easing stiffness, slowness and tremor. According to the UK SmPC, adults can take it for idiopathic Parkinson's disease on its own or together with levodopa, including in later stages when the effect of levodopa wears off between doses. It is also licensed for the symptomatic treatment of moderate to severe idiopathic restless legs syndrome (RLS), at much lower doses.

This page lists 0.125 mg, 0.25 mg and 0.5 mg tablets, each in packs of 30, 60, 90 or 180. These figures refer to pramipexole dihydrochloride monohydrate (the salt). UK packs are labelled by the base instead, so 0.125 mg of salt equals 0.088 mg of base, 0.25 mg equals 0.18 mg and 0.5 mg equals 0.35 mg. The product is imported. The three strengths listed here correspond to standard (immediate-release) tablets taken three times a day in Parkinson's disease. The Mirapex name is not licensed in the UK.

For Parkinson's disease the daily amount is split into three equal doses. Treatment starts at 0.125 mg of salt three times a day in week one, moves to 0.25 mg three times a day in week two and 0.5 mg three times a day in week three. After that, the daily total may be increased by 0.75 mg each week if necessary, up to a maximum of 4.5 mg of salt a day. For restless legs the starting dose is 0.125 mg once daily, two to three hours before bed, which can be stepped up every four to seven days to a ceiling of 0.75 mg; the benefit is reviewed after three months. Reduced kidney function calls for lower or less frequent doses. In Parkinson's disease the medicine is never stopped abruptly but tapered, because sudden withdrawal can cause a serious reaction resembling neuroleptic malignant syndrome or a dopamine agonist withdrawal syndrome.

Pramipexole is a prescription-only medicine (POM) in the UK. The Boehringer Ingelheim brand is called Mirapexin there, with standard tablets of 0.088 mg, 0.18 mg, 0.35 mg and 0.7 mg of base and prolonged-release tablets from 0.26 mg to 3.15 mg. Generic standard tablets and other prolonged-release brands, such as Pipexus, are also available. Treatment is started and adjusted by the prescriber, usually a specialist.

Mirapex can cause drowsiness and, occasionally, falling asleep suddenly during daily activities without warning, so anyone affected must not drive or operate machinery. Impulse control problems, including compulsive gambling, spending, binge eating and increased sex drive, are recognised; patients and carers should be told about them and monitored regularly. Mostly visual hallucinations, low blood pressure on standing and, in restless legs, augmentation (symptoms starting earlier in the day and spreading) may occur. Antipsychotic medicines should not be combined with it, cimetidine and amantadine can reduce its clearance by the kidneys, and alcohol or other sedatives add to drowsiness. Regular eye checks are recommended.

In Parkinson's disease the most frequently reported effects include nausea, dizziness, sleepiness, involuntary movements (dyskinesia), low blood pressure, insomnia, constipation, hallucinations, headache and tiredness. In restless legs, nausea, headache, dizziness and fatigue are most common. Ankle swelling, confusion, weight changes and unusual dreams are other possible effects. The only absolute contraindication in the SmPC is hypersensitivity to pramipexole or the tablet ingredients.