Antipsychotics | Antidepressants
Several adverse events can occur in patients taking typical antipsychotics
and to a lesser degree in patients taking atypical antipsychotics.
Dystonic reactions are characterized by extreme muscle contraction
and rigidity in a patient with stable vital signs and a clear sensorium.
These occur most frequently with high-potency, first-generation antipsychotics
(Moleman et al. 1982; Schillevoort et al. 2001).
Young males are particularly susceptible to dystonic reactions.
Most dystonic reactions are extremely uncomfortable and frightening
to the patient. Treatment of these reactions is typically 1–2
mg of benztropine via the oral or intramuscular route. An alternative
is diphenhydramine in doses of 25–50 mg via the oral or
intramuscular route. Dystonias that include the eyes, the so-called
oculogyric crises, are particularly frightening, as are dystonias
that cause laryngeal spasms, which can compromise the airway. These
reactions should be treated with 50 mg of intravenous diphenhydramine,
which provides rapid relief. Maintenance treatment of 1–2
mg of benztropine twice a day or 25–50 mg of diphenhydramine twice
a day should be initiated after the acute reaction has resolved
(Keepers et al. 1983).