Akathisia

An imbalance between the noradrenergic and dopaminergic systems caused by the dopamine receptor antagonists.

Days to weeks

Subjective feeling of restlessness in the lower extremities, often manifested in an inability to sit still.

Worsens with increasing dose.

Lower dose of antipsychotic.

Switch to an atypical antipsychotic.

Add propranolol 20 mg p.o. BIDTID.

Benzodiazepines and clonidine are alternative treatments.

Dystonia

Dopaminergic hyperactivity in the basal ganglia that occurs when the central nervous system levels of the dopamine receptor antagonist drug begin to fall between doses.

Hours or days

Uncontrollable and painful tightening of muscles often involving spasms of neck, back, tongue, or muscles controlling lateral eye movement.

Laryngeal involvement may compromise the airway and result in ventilatory difficulties.

Risk factors include: young age, male gender, previous episodes of acute dystonia, recent cocaine use, hypocalcemia, and dehydration.

Acute dystonia:

Diphenhydramine 25 mg IM/IV.

Benztropine 2 mg IV.

Follow with oral anticholinergic due to long half-lives of antipsychotics and/or continuing antipsychotic therapy.

Prophylaxis:

Diphenhydramine 25-50 mg p.o. BIDTID.

Benztropine 1-2 mg p.o. BID.

Trihexyphenidyl 5-10mg p.o. BID.

Parkinsonian syndrome

Disproportionally less dopamine than acetylcholine in the basal ganglia.

Weeks to months

Similar features of classic idiopathic Parkinson disease, such as:

Diminished range of facial expression

Cogwheel rigidity

Slowed movements

Drooling

Small handwriting

Regular, coarse tremor.

“Rabbit syndrome” consisting of fine, rapid movements of the lips.

Can distinguish from idiopathic Parkinson disease through symmetric, bilateral signs from the onset rather than hemiparkinsonism.

Diphenhydramine 25-50 mg p.o. BIDTID.

Benztropine 1-2 mg p.o. BID.

Trihexyphenidyl 5-10 mg p.o. BID.

Perform trial of withdrawing anticholinergic after 4-6 weeks to assess if the patient has developed a tolerance for the parkinsonian effects.

Tardive dyskinesia

Supersensitivity of postsynaptic dopamine receptors induced by long-term blockade.

Onset >6 months

Involuntary facial and oral movements, choreoathetoid movements of the extremities, and involuntary movements of the extremities and trunk.

Risk factors include increasing age, duration of exposure, women, substance abuse, conventional antipsychotics.

Clozapine appears to be the only agent that has not been shown to cause tardive dyskinesia.

Evaluation before treatment and every 6-12 months. No definitive treatment exists. Some studies have shown vitamin E to have some benefit, but overall data has been inconclusive.