Medication
PD medications are used to control symptoms and do not reverse the disorder. The type of medication, the dosage and timing is determined by the doctor after consultation with the person with PD and their caregiver or family and is tailored to the individual. It is important that the person with PD adhere to the schedule recommended by their doctor in order to gain the greatest benefit from the medications.
Side effects can occur with all PD medications and the treating doctor should discuss them with the person with PD and their carer before any new medication is introduced.
The doctor, in particular a PD specialist neurologist, is the best person to determine if the PD medications are causing any adverse responses and make the necessary adjustments to reverse or minimise side effects.
Other medications, such as herbal supplements and other remedies, may interact with PD medications. The person’s doctor and pharmacist are the best people to talk to regarding potential medicine interactions.
Levodopa with carbidopa or benserazide
Levodopa is usually the first-line medicine prescribed for PD. Levodopa replaces the dopamine that is no longer produced naturally by the brain. Levodopa is converted into dopamine in the brain and is taken to improve motor symptoms, such as stiffness and slowness of movement and tremor.
The common brands available in Australia include Sinemet®, Madopar® and Kinson® which come in various preparations and strengths. They are available in immediate release, long acting (e.g. Sinemet CR®, Madopar HBS®) and rapid acting (when dissolved in water (e.g. Madopar Rapid®)). Levodopa with carbidopa or benserazide products are also available in combination with other medicines (e.g. Stalevo®), and in gel form (e.g. Duodopa®).
Examples of possible side effects include: involuntary movements (dyskinesia), changes in mood or behaviour, confusion, nausea, light headedness, lowered blood pressure.
Dopamine agonists
Dopamine agonists work by stimulating the dopamine receptors of the brain. They are considered not to be as powerful as levodopa however they can be very effective at controlling involuntary movements (dyskinesia) associated with taking levodopa and motor fluctuations(‘off’ times when symptoms re-emerge). They can be taken either alone or in combination with levodopa across the stages of PD.
Dopamine agonists available in Australia include pramipexole (e.g. Sifrol®), cabergoline (e.g. Cabaser®), rotigotine (e.g. Neupro®), apomorphine (e.g. Movapo®).
Examples of possible side effects include: impulse control disorders (e.g. gambling), hallucinations and confusion, daytime sleepiness, swelling in legs.
COMT Inhibitors
COMT inhibitors work by blocking an enzyme present in the body which converts the levodopa into a form that cannot be used by the body. By blocking this process the amount of dopamine available in the brain increases. They are often commenced when ‘wearing off’ or motor fluctuations develop. Entacapone (e.g. Comtan®) is the COMT inhibitor available in Australia.
Examples of possible side effects include: diarrhoea, increase side effects of levodopa medications e.g. dyskinesia, confusion and hallucinations.
MAO-B Inhibitors
MAO-B inhibitors block an enzyme present in the brain that breaks down dopamine so that more dopamine is available for treating motor symptoms. The inhibitors also have some effect in controlling the motor symptoms and as such may be the first medicine of use in the early stages. MAO-B inhibitors may be used initially on their own or in combination with other PD medications.
Selegiline (e.g. Elderpryl®) and rasagiline (e.g. Azilect®) are the common MAO-B inhibitors used.
Examples of possible side effects include: dry mouth, light headedness, constipation, confusion and hallucinations in the elderly.
Amantadine
This medicine is used along with levodopa to treat dyskinesias.
Anticholinergics
These medicines are used to treat tremor and dystonia or muscle cramps due to PD. The common ones available include trihexyphenidyl (e.g. Artane®) and benzatropine (e.g. Benztrop®), however as they both may cause confusion and hallucinations, they are usually avoided in older adults.
Examples of possible side effects include: Confusion and hallucinations, decreased short term memory, dry mouth, blurred vision, urinary retention.