Merck Manual

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Treatment of Acute Adverse Effects of Antipsychotics

Treatment of Acute Adverse Effects of Antipsychotics

Symptoms

Treatment

Comments

Acute dystonic reactions (eg, oculogyric crisis, torticollis)

Benztropine 2 mg IV or IM (may be repeated once in 20 minutes)

Diphenhydramine 50 mg IV or IM every 20 minutes for 2 doses

Benztropine 2 mg orally may prevent dystonia when given with an antipsychotic.

Laryngeal dystonia

Lorazepam 4 mg IV over 10 minutes, then 1–2 mg IV slowly

Intubation may be needed.

Akinesia, severe parkinsonian tremors, bradykinesia

Benztropine 1–2 mg orally 2 times a day

Diphenhydramine 25–50 mg orally 3 times a day

In patients with akinesia, the antipsychotic may have to be stopped, and one with a lower potency used.

Akathisia (with other extrapyramidal symptoms)

Amantadine 100–150 mg orally 2 times a day

Benztropine 1–2 mg orally 2 times a day

Biperiden 1–4 mg orally 2 times a day

Procyclidine 2.5–10 mg orally 2 times a day

Propranolol 10–30 mg orally 3 times a day

Trihexyphenidyl 2–7 mg orally 2 times a day or 1–5 mg orally 3 times a day (or for the sustained-release form, 2–7 mg 2 times a day)

The causative antipsychotic should be stopped, or a lower dose used.

Akathisia associated with extreme anxiety

Lorazepam 1 mg orally 3 times a day

Clonazepam 0.5 mg orally 2 times a day