Kventiax Sr (Quetiapine)

• Quetiapine is used to manage psychiatric conditions that involve dysregulation of dopamine and serotonin pathways.
• Schizophrenia: helps reduce psychotic symptoms such as hallucinations and delusions.
• Bipolar disorder (manic episode): stabilises mood and diminishes elevated energy, irritability and risky behaviour.
• Bipolar disorder (depressive episode): alleviates depressive symptoms and improves overall functioning.
• Adjunctive treatment of major depressive disorder: enhances antidepressant response when added to standard therapy.
• Schizoaffective disorder: controls both psychotic and mood components of the illness.

• Quetiapine acts as an antagonist at multiple neurotransmitter receptors, most notably serotonin 5‑HT2A and dopamine D2 receptors, which reduces psychotic and mood symptoms. Additional antagonism at histamine H1, adrenergic α1, and various other receptors contributes to its sedative, antihistaminic, and orthostatic effects, while the overall receptor profile supports mood stabilisation and antidepressant augmentation.

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

Common Side Effects

• Sedation or drowsiness
• Dizziness or light‑headedness
• Dry mouth
• Moderate weight gain

Serious or Rare Side Effects

• Agranulocytosis (dangerously low white‑blood‑cell count)
• Neuroleptic malignant syndrome (potentially life‑threatening reaction)
• Tardive dyskinesia (involuntary, repetitive movements).

• When prescribing or dispensing Kventiax Sr, several safety considerations should be observed.
• Dose titration: start low and increase gradually as directed by the prescriber.
• Cardiovascular monitoring: watch for orthostatic hypotension and QT‑interval prolongation.
• Metabolic monitoring: assess weight, glucose, and lipid levels regularly.
• CNS effects: caution with activities requiring alertness due to possible sedation.
• Pregnancy and lactation: use only if benefits outweigh risks; data are limited.
• Store at ambient temperature below 25°C: keep in original container, protect from moisture and light.

Quetiapine can interact with several drug classes, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole) may raise quetiapine levels and increase toxicity.
• Co‑administration with other CNS depressants (e.g., benzodiazepines, alcohol) can cause profound sedation and respiratory depression.
• Medications that prolong the QT interval (e.g., certain antiarrhythmics) may increase risk of cardiac arrhythmias.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine) can reduce quetiapine exposure, possibly diminishing efficacy.
• Antihypertensive agents may have additive hypotensive effects.
• Anticholinergic drugs may exacerbate dry mouth and constipation.