OVERDOSE
Selegiline
No specific information is available about clinically
significant overdoses with selegiline hydrochloride. However,
experience gained during selegiline's development reveals
that some individuals exposed to doses of 600 mg d,l-selegiline
suffered severe hypotension and psychomotor agitation.
Since the selective inhibition of MAO B by selegiline
hydrochloride is achieved only at doses in the range recommended
for the treatment of Parkinson's disease (e.g., 10 mg/day),
overdoses are likely to cause significant inhibition of
both MAO A and MAO B. Consequently, the signs and symptoms
of overdose may resemble those observed with marketed
non-selective MAO inhibitors [e.g., tranylcypromine, isocarboxazide
, and phenelzine].
Overdose with Non-Selective MAO Inhibition
NOTE: This section is provided for reference;
it does not describe events that have actually been observed
with selegiline in overdose.
Characteristically, signs and symptoms of non-selective
M.O. overdose may not appear immediately. Delays of up
to 12 hours between ingestion of drug and the appearance
of signs may occur. Importantly, the peak intensity of
the syndrome may not be reached for upwards of a day following
the overdose. Death has been reported following overdosage.
Therefore, immediate hospitalization, with continuous
patient observation and monitoring for a period of at
least two days following the ingestion of such drugs in
overdose, is strongly recommended.
The clinical picture of M.O. overdose varies considerably;
its severity may be a function of the amount of drug consumed.
The central nervous and cardiovascular systems are prominently
involved.
Signs and symptoms of overdosage may include, alone or
in combination, any of the following: drowsiness, dizziness,
faintness, irritability, hyperactivity, agitation, severe
headache, hallucinations, trismus, opisthotonus, convulsions,
and coma; rapid and irregular pulse, hypertension, hypotension
and vascular collapse; precordial pain, respiratory depression
and failure, hyperpyrexia, diaphoresis, and cool, clammy
skin.
Treatment Suggestions for Overdose
NOTE: Because there is no recorded experience
with selegiline overdose, the following suggestions are
offered based upon the assumption that selegiline overdose
may be modeled by non-selective M.O. poisoning. In any
case, up-to-date information about the treatment of overdose
can often be obtained from a certified Regional Poison
Control Center. Telephone numbers of certified Poison
Control Centers are listed in the Physicians GenRx.
Treatment of overdose with non-selective MAOIs is symptomatic
and supportive. Induction of emesis or gastric lavage
with instillation of charcoal slurry may be helpful in
early poisoning, provided the airway has been protected
against aspiration. Signs and symptoms of central nervous
system stimulation, including convulsions, should be treated
with diazepam, given slowly intravenously. Phenothiazine
derivatives and central nervous system stimulants should
be avoided. Hypotension and vascular collapse should be
treated with intravenous fluids and if necessary, blood
pressure titration with an intravenous infusion of a dilute
pressor agent. It should be noted that adrenergic agents
may produce a markedly increased pressor response.
Respiration should be supported by appropriate measures,
including management of the airway, use of supplemental
oxygen, and mechanical ventilatory assistance, as required.
Body temperature should be monitored closely. Intensive
management of hyperpyrexia may be required. Maintenance
of fluid and electrolyte balance is essential.
CONTRAINDICATIONS
Selegiline hydrochloride is contraindicated in patients
with a known hypersensitivity to this drug.
Selegiline hydrochloride is contraindicated for use with
meperidine. This contraindication is often extended to
other opioids. (See DRUG INTERACTIONS.)
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