asenapine

Asenapine is an atypical antipsychotic medication used to treat schizophrenia and acute manic or mixed episodes in bipolar I disorder. It is administered as a sublingual tablet to improve absorption and avoid first-pass metabolism. After placement under the tongue, the tablet dissolves; patients should not eat or drink for about 10 minutes to ensure absorption.

Pharmacology: Asenapine acts primarily as an antagonist at dopamine D2 and serotonin 5-HT2A receptors, with additional activity at other serotonin receptors (such as 5-HT2C and 5-HT1A) and at histamine H1 and alpha-adrenergic receptors. This receptor profile is thought to contribute to its antipsychotic effects and side-effect pattern.

Administration and dosing: The dose is determined by a clinician and is typically given once daily, with adjustments for efficacy and tolerability. The sublingual route is essential due to the drug’s low oral bioavailability.

Adverse effects and safety: Common adverse events include somnolence, dizziness, akathisia, and extrapyramidal symptoms. The sublingual form can cause oral hypoesthesia and taste disturbance. Like other antipsychotics, asenapine may be associated with weight gain and metabolic changes and can increase prolactin levels; higher doses may prolong the QT interval. All antipsychotics carry a general warning for increased mortality in elderly patients with dementia-related psychosis.

Precautions and interactions: Use with caution in hepatic impairment and when combined with other QT-prolonging medications. Patients should inform clinicians about all medications and supplements to assess potential interactions.