Antipsychotic Side Effects: EPS, NMS and Metabolic Risks

Antipsychotic side effects are a rich source of exam questions because every drug group has a typical pattern. If you can match the adverse effect to the mechanism and the drug, you can answer most of these items. The main idea is that dopamine blockade and other receptor effects explain the problems.

Extrapyramidal effects

• Acute dystonia: sudden muscle spasms of the neck, jaw or eyes, usually within days, treated with an anticholinergic drug
• Parkinsonism: tremor, rigidity and bradykinesia, managed by dose reduction or switching
• Akathisia: inner restlessness, often treated by lowering the dose or using a beta-blocker
• Tardive dyskinesia: involuntary movements of the mouth and face after long-term use, which may persist

Risk is highest with high-potency first-generation drugs such as haloperidol.

Neuroleptic malignant syndrome

A rare emergency with fever, severe muscle rigidity, altered mental state, autonomic instability and raised creatine kinase. Stop the antipsychotic, give supportive care and cooling, and consider dantrolene or bromocriptine in severe cases. Compare it with serotonin syndrome, which has clonus and hyperreflexia and a faster onset.

Hyperprolactinemia

Dopamine blockade in the pituitary raises prolactin and can cause galactorrhea, menstrual disturbance and sexual dysfunction. Risperidone and amisulpride are commonly associated with this effect.

Metabolic effects

Olanzapine and clozapine are associated with weight gain, diabetes and dyslipidemia. Monitor weight, waist circumference, blood pressure, glucose and lipids at baseline and regularly.

Cardiac effects

Several antipsychotics prolong the QT interval. Check the electrocardiogram when risk factors are present and avoid combining QT-prolonging drugs.

Clozapine

Clozapine is used for treatment-resistant schizophrenia. Key risks include agranulocytosis, which needs regular blood count monitoring, myocarditis, seizures, drooling and constipation. Constipation can become severe, so ask about bowel habits.

Other points

Aripiprazole is a partial agonist and may cause akathisia. Quetiapine causes sedation and orthostatic hypotension. Older adults with dementia have an increased mortality risk with antipsychotics.

A classic exam pattern

A patient started on haloperidol develops sudden neck twisting and eye deviation. The diagnosis is acute dystonia, and the treatment is an anticholinergic agent.

Study tips

• Build a table of drug, key side effect and monitoring
• Compare NMS and serotonin syndrome
• Review each wrong answer for the receptor clue

This article is for exam revision and does not replace current clinical guidelines. Practice more with the Namazj free trial.