EMQs in Clinical Medicine.pdf - Peshawar Medical College

104 Neurology
41 Treatment of Parkinson’s disease
Answers: G J C A H
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Improvement of tremor in a 70-year-old patient with Parkinson’s
disease on treatment with levodopa.
Benzhexol is a muscarinic acetylcholine receptor antagonist that is useful
in treatment of parkinsonian tremor. Such anti-muscarinics are useful in
treating tremor and rigidity, and in reducing sialorrhoea, but they have
little effect on bradykinesia.
Control of vomiting in a patient being treated for Parkinson’s disease.
Domperidone is the antiemetic of choice because it does not penetrate
the blood–brain barrier and can be given with centrally acting dopamine
agonists to counteract their emetogenic effect.
A 65-year-old man with Parkinson’s disease cannot tolerate
levodopa-based therapy despite careful titration.
Bromocriptine is a dopamine receptor agonist and is indicated if
levodopa therapy is felt to be no longer adequate or if the patient
cannot tolerate levodopa therapy. The use of bromocriptine is limited by
its adverse effects, which include hypotension and fibrotic reactions,
e.g. pulmonary fibrosis.
A patient on therapy for Parkinson’s disease requires urgent treatment
for acute psychosis.
The dose of the responsible anti-parkinsonian drug should be reduced.
Clozapine is an atypical antipsychotic and is thus preferred to the typical
antipsychotics which have more marked extrapyramidal side effects.
A 75-year-old man with severe Parkinson’s disease with symptoms
that remain uncontrolled on maximum oral therapy.
Apomorphine by subcutaneous injection/infusion is indicated if motor
symptoms of Parkinson’s disease remain refractory to maximal therapy
with levodopa and other anti-parkinsonian drugs. Hospital admission
is required for initiation of treatment. Adverse effects of nausea and
vomiting are very common and so pre-treatment with domperidone is
standard.