Treatment of Parkinson’s Disease
Posted by Eamonn Brady on
Eamonn Brady is a pharmacist and the owner of Whelehans Pharmacy, Pearse St, Mullingar. If you have any health questions e-mail them to info@whelehans.ie
This is continuation of last week’s article on Parkinson’s. There is no cure for Parkinson’s but treatments can ease symptoms and slow progression. It can take 8 to 10 weeks from the start of treatment before the patient notices improvement in symptoms.
Levodopa
Levodopa tends to give a good improvement in symptoms. Levodopa is converted to dopamine in the brain. The dose is started low but tends to be increased to control symptoms. Levodopa is always used in combination with another medicine to prevent side effects (either benserazide or carbidopa). Brands available include Madopar® and Sinemet®. Side effects from Levodopa tend to be rare at low doses. Nausea is the most common side effect. Other side effects which may occur include vomiting, dizziness, low blood pressure; however these often ease after a few days of use. Levodopa can also cause movement disorders (head nodding, jerking and twitches) if used at too high a dose. The effect of Levodopa tends to wear off over time, usually over a period of 3 to 5 years.
Dopamine agonists
Dopamine agonists mimic dopamine. Ropinirole (Requip®), pramipexole (Mirapexin®) and rotigotine (Neupro® patch) are used most commonly. Initial side-effects are similar to levodopa (nausea, vomiting and dizziness) however side-effects tend to ease within a few days or weeks. Despite being slight less effective than Levodopa, one potential advantage of them as compared with levodopa is that they have less risk of causing movement disorders (described above). A dopamine agonist may be used in combination with levodopa as the condition gets worse. In trials comparing levodopa and dopamine agonists, symptoms of Parkinson’s improved with levodopa by about 40 to 50% as compared with approximately 30% with dopamine agonists.
Monoamine oxidase-B inhibitors
Sometimes used as alternative to levodopa for early Parkinson’s. They include selegiline (Eldepryl®) and rasagiline (Azilect®). They work by blocking the effect of monoamine-oxidase-B (MAOB) in the brain, a chemical that prevents the breakdown of levodopa and dopamine. Blocking the effect of MAO-B means the effect of dopamine lasts longer. MAOBs are often used in combination with levodopa as the condition progresses.
Other medication used for Parkinson's disease
Catechol-O-methyltransferase (COMT) inhibitors have become available in the last 20 years. Entacapone (Comtess® and also an ingredient in Stalevo®) is an example. A COMT inhibitor is often added to levodopa (as it increases its effect) when levodopa is not controlling symptoms sufficiently alone or where the effect of levodopa wears off. This is why Stalevo® has grown in popularity in recent years.
Upcoming Alzheimer’s Information Evening in Mullingar
Whelehans Pharmacy host a Dementia and Alzheimer’s Information evening in the Greville Arms Hotel on Thursday April 27th at 7pm. The event is free of charge and all are welcome. Speakers include:
- Dr Michael O’Cuill, Consultant Psychiatrist; leading Dementia expert in Westmeath.
- Mr Eamonn Brady, pharmacist at Whelehans Pharmacy.
- Donal Murphy, Regional Manager, Alzheimer Society Ireland
Book your place for the evening by calling Whelehans at 04493 34591 or e-mail health@whelehans.ie
To be continued…next week I will conclude my Parkinson’s series by describing non drug options and practical tips.