Ketipinor (Quetiapine)

Quetiapine is used in psychiatric disorders that involve dysregulation of dopamine and serotonin pathways.

• Schizophrenia: reduces positive and negative symptoms, helping patients achieve better overall functioning and social integration.
• Bipolar disorder: stabilizes mood during both manic and depressive phases, decreasing episode frequency and severity.
• Major depressive disorder (adjunct): enhances the therapeutic response when added to standard antidepressant regimens, improving remission rates.

• Quetiapine exerts its antipsychotic effect primarily by antagonizing serotonin 5‑HT₂A and dopamine D₂ receptors, thereby reducing dopaminergic and serotonergic hyperactivity. It also blocks histamine H₁ and adrenergic α₁ receptors, contributing to its sedative and antihypertensive properties, and acts as a partial agonist at 5‑HT₁A receptors, which may enhance mood and anxiety regulation. The combined receptor profile results in a broad therapeutic spectrum across psychotic, mood and anxiety disorders.

Quetiapine may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Drowsiness or sedation: excessive sleepiness, especially after dose initiation.
• Dry mouth: reduced salivation leading to discomfort.
• Constipation: slowed gastrointestinal motility.
• Weight gain: gradual increase in body weight over time.
• Dizziness: light‑headed feeling, often orthostatic.
• Increased appetite: heightened desire for food, contributing to weight changes.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: life‑threatening reaction with fever, rigidity, autonomic instability.
• Agranulocytosis: severe drop in white blood cells, increasing infection risk.
• Tardive dyskinesia: involuntary, repetitive movements, potentially irreversible.
• Severe hypotension: marked drop in blood pressure, especially on standing.
• Seizures: occurrence of convulsive episodes.
• Elevated blood glucose or diabetes: hyperglycemia requiring monitoring.

When prescribing quetiapine, clinicians should consider several precautionary measures to ensure safe use.

• Dose titration: start low and increase gradually to minimize side effects.
• Cardiovascular monitoring: assess blood pressure and heart rate, especially in patients with orthostatic risk.
• Metabolic surveillance: monitor weight, glucose, and lipid levels regularly.
• CNS depression: caution when combined with other sedatives or alcohol.
• Pregnancy and lactation: evaluate risk‑benefit ratio; use only if clearly needed.
• Store at ambient temperature: keep tablets in original container, protect from moisture and light.

Quetiapine interacts with several drug classes; awareness of these interactions helps prevent adverse events.

Major Interactions (Avoid)

• CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may raise quetiapine plasma levels, increasing toxicity risk.
• CNS depressants (e.g., benzodiazepines, opioids): can enhance sedation and respiratory depression.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may lower quetiapine concentrations, reducing efficacy.
• Antihypertensives: additive hypotensive effect, monitor blood pressure.
• Anticholinergic agents: may worsen dry mouth and constipation.
• Antidepressants (e.g., SSRIs): monitor for serotonin syndrome signs.