Ketilept Prolong (Quetiapine Fumarate)

• Quetiapine acts on neurotransmitter pathways implicated in psychotic and mood disorders.
• Schizophrenia: reduces hallucinations, delusions and other psychotic symptoms.
• Bipolar disorder (manic and depressive episodes): stabilises mood and helps prevent recurrence of manic or depressive episodes.
• Major depressive disorder (adjunctive): enhances response to standard antidepressant therapy when added to treatment regimens.

• Quetiapine exerts its therapeutic effect by antagonising dopamine D2 receptors and serotonin 5‑HT2A receptors, while also modulating 5‑HT1A, histamine H1 and adrenergic α1 receptors. This combined receptor profile reduces dopaminergic over‑activity and balances serotonergic transmission, contributing to antipsychotic and mood‑stabilising actions.

Quetiapine may cause a range of adverse reactions, which are generally categorized by frequency.

Common Side Effects

• Drowsiness or sedation
• Dry mouth
• Constipation
• Weight gain
• Dizziness
• Orthostatic hypotension

Serious or Rare Side Effects

• Neuroleptic malignant syndrome
• Tardive dyskinesia
• Severe hypotension
• Elevated blood glucose or new‑onset diabetes
• Leukopenia or agranulocytosis
• Emergence of suicidal thoughts or behaviours

• Before initiating quetiapine therapy, several safety considerations should be reviewed.
• Assess cardiovascular status: monitor blood pressure and heart rate, especially in patients with pre‑existing hypotension.
• Screen for metabolic risk: evaluate glucose, lipid profile, and weight changes during treatment.
• Review psychiatric history: consider risk of suicidal ideation, particularly in young adults.
• Avoid abrupt discontinuation: taper dose under medical supervision to reduce withdrawal symptoms.
• Pregnancy and lactation: discuss potential risks with the prescriber; use only if benefits outweigh risks.
• Store below 25°C: keep in the original container, protect from moisture and light.

Quetiapine can interact with other medicines, altering its effectiveness or safety profile.

Major Interactions (Avoid)

• CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase quetiapine plasma levels, risking toxicity.
• CNS depressants (e.g., benzodiazepines, opioids): additive sedation and respiratory depression.
• Antihypertensive agents: may potentiate orthostatic hypotension.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce quetiapine exposure, decreasing efficacy.
• Other antipsychotics: increase risk of QT prolongation.
• Anticholinergic drugs: may exacerbate dry mouth and constipation.