Information Sheet
Contact the Parkinson’s Disease Society freephone helpline for advice and information on 0808 800 0303
3
If the oending drug is stopped, will the
drug-induced parkinsonism improve and
if so, how long will this take?
Generally, 60% of people will recover within
two months, and often within hours or days,
of stopping the oending drug. However, some
people may take as long as two years. One
study reported that 16% of cases went on to
be conrmed to have idiopathic Parkinson’s.
These people were probably going to develop
Parkinson’s at some stage in the future in any
event, but the oending drug ‘unmasked’ an
underlying dopamine deciency. This theory is
supported by research studies with specialist
PET scans.
What other treatment is available?
In many cases, the rst approach to treatment
will be to try stopping the oending drug
for a sucient length of time, reducing it, or
changing it to another drug that may be less
likely to cause drug-induced parkinsonism.
Please note: you should not stop taking any
drug because you think it is causing drug-
induced parkinsonism, or worsening existing
Parkinson’s without rst discussing the
situation with your doctor. Some drugs need
to be withdrawn slowly, particularly if
the person has been taking the drug for a
considerable time, and problems can arise if
they are withdrawn abruptly.
Sometimes, for medical reasons, the person
cannot stop taking the drug that causes
drug-induced parkinsonism. Where this
is the case, the benets of the drug need
to be weighed against the side eects of
parkinsonism. Sometimes, adjusting the dose
of the neuroleptic drug downwards to a level
that does not cause parkinsonism may help.
However, this is not always possible, without
taking the dose to a sub-therapeutic level
(i.e. a level where it is not as eective at
treating the psychotic illness for which it is
prescribed). Usually, changing the medication
to an atypical neuroleptic is the best approach.
If it is not possible to stop taking the oending
drug, then anticholinergic drugs may be used.
However, these are best avoided in older
people, because they may cause confusion,
as well as worsening tardive dyskinesia.
Amantadine (Symmetrel), another drug
used to treat Parkinson’s, can also be used
to treat drug-induced parkinsonism if the
person cannot stop taking the oending
drug. However, like anticholinergic drugs,
amantadine may also cause confusion, and
sometimes psychosis in older people, and
therefore is more suitable for younger people
with drug-induced parkinsonism.
Can these drugs aggravate existing
idiopathic Parkinson’s disease?
Yes. Stopping the medication (where possible)
may be enough to relieve the drug-induced
parkinsonism, although improvements can
take several months.
Can illegal drugs such as heroin cause
drug-induced parkinsonism?
In the late 1970s, a group of drug users in
California took synthetic drugs, manufactured
illegally, as a cheap alternative to heroin. One
of these addicts, aged 23 years, became ill
and over several days developed symptoms
of parkinsonism, such as tremor, rigidity and
akinesia. When he was treated with anti-