Medications


(Note: (added 9/3/98): Since I first wrote this a number of new medications have become available for the treatment of PD. These include, Requip, Mirapex and Tasmar. I have not included them because they have not as yet, or in the case of Tasmar have only just, been released in Australia. Having no exprience of them I do not feel competant to discuss them at this time.)

In the first instance PD is treated by a range of drugs which fall into the following categories:

Dopamine replacement

For most PWP these are the most affective drugs. A proportion of the dopamine precursor, levodopa, crosses the blood/brain barrier into the brain, where it is converted to dopamine.

Smooth delivery

Slow release versions of these drugs are used to provide longer 'on' periods, and some PWP have successfully used liquid Sinemet to achieve the same result.


Note: Sinemet CR should never be crushed or chewed as this destroys its slow release properties

Problems

The use of levodopa can have the following side effects:

And after prolonged use:

The PD experience

Timing of medication

Many PWP find that their medications are most effective if taken 30-20 minutes before food. Chemists, however, tend to dispense these drugs with the advice that they should be taken with meals in order to minimise nausea. If nausea is a problem discuss with your doctor the use of anti-nausea drugs such as Motilium.

Starting levodopa

When to start levodopa is probably the biggest decision that needs to be made in the early years of PD. A balance needs to be struck between the need to delay its use as long as possible and maintaining the PWP's quality of life at a reasonable level. As value judgments are involved it is impossible to set hard and fast rules, but it is probably easier for the doctor to give his advice if the PWP can clearly indicate their own priorities and expectations.




Anticholinergic drugs

These work to restore the dopamine/acetycholine balance by suppressing the acetycholine. They are used for patients with mild symptoms and are most effective against tremor.

Problems

PWP on anticholinergics may experience:




Dopamine Agonists

The agonists stimulate the dopamine receptors in the brain, causing them to make a more efficient use of the available dopamine.

Problems

Agonists can cause:

The PD Experience

Reading the list of possible side effects makes you wonder why anyone would take such drugs. In fact most PWP find that the agonists allow them to use less levadopa with an overall reduction in side effects. Most of the PD drugs currently in development are agonists.




Deprenyl

Studies indicate that deprenyl (selegiline) slows the progress of PD. It is used in the early stages to delay the use of other PD medications. When used with dopamine replacement medications it enhances the effect of the levadopa, which means that less levadopa need be taken.

Problems

Prozac (fluoxetine) and Pethidine should be used with caution by anyone on Deprenyl.

The use of Deprenyl may have the following side effects:





Symmetrel

Used in the early stages of PD, symmetrel (amantadine) is thought to work by releasing dopamine from nerve endings in the brain. It is more effective against rigidity and stiffness than tremor
Problems Symmetrel should be avoided by PWP who also have severe kidney, heart or liver conditions.




Apomorphine

Apomorphine is used in late stage PD to counteract the freezing and extreme bradykinesia. It can be injected subcutaneously or taken as a lozenge under the tongue.

Problems

Possible side effects can include:

The PD Experience

The nausea experienced as a side effect is so usual that doctors write the proscription for motilium on the same form. The response to apomorphine is rapid (5-10 minutes) but it only lasts 30 minutes or so. A very useful tool when faced with something that must be done at a given time.




Motilium

Motilium (domperidone) is used to prevent the nausea which is associated with many PD medications. It has the advantage of not making PD symptoms worse.


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