Kvelux Sr (Quetiapine)

Quetiapine is used in several psychiatric conditions that involve dysregulated dopamine and serotonin pathways.

• Schizophrenia: reduces hallucinations, delusions and thought disorder.
• Bipolar disorder (manic and depressive episodes): helps control mood swings and prevents relapse.
• Adjunct treatment of major depressive disorder: augments antidepressant response in patients with inadequate improvement.

• Quetiapine acts as an antagonist at serotonin 5‑HT2A, dopamine D2, histamine H1, and adrenergic α1 receptors. By blocking these receptors, it modulates neurotransmission in cortical and limbic regions, decreasing dopaminergic overactivity linked to psychosis while balancing serotonergic signaling that influences mood and cognition.

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

Common Side Effects

• Drowsiness or sedation: feeling unusually sleepy.
• Dry mouth: reduced salivation leading to discomfort.
• Constipation: infrequent or difficult bowel movements.
• Weight gain: increase in body weight over time.
• Orthostatic hypotension: drop in blood pressure upon standing.
• Elevated triglycerides: rise in blood lipid levels.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: life‑threatening reaction with fever and muscle rigidity.
• Agranulocytosis: severe drop in white blood cells.
• Tardive dyskinesia: involuntary, repetitive movements.
• Suicidal ideation: emergence or worsening of suicidal thoughts.
• Severe allergic reactions: rash, swelling, or breathing difficulty.

Before initiating quetiapine therapy, consider the following safety measures.

• Cardiovascular assessment: evaluate for history of heart disease or arrhythmias.
• Metabolic monitoring: check blood glucose, lipids and weight regularly.
• CNS depression: avoid alcohol or other sedatives that may enhance drowsiness.
• Pregnancy and lactation: discuss risks with a healthcare professional before use.
• Elderly patients: start at low dose and monitor for falls or confusion.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Quetiapine can interact with several drug classes, affecting its efficacy or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase quetiapine plasma levels.
• CNS depressants (e.g., benzodiazepines, opioids): can cause excessive sedation or respiratory depression.
• Antihypertensive agents: additive effect on blood pressure lowering.

Moderate Interactions (Monitor Closely):\n- CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce therapeutic effect.

• Anticholinergic drugs: may worsen dry mouth and constipation.
• Lithium: concurrent use may increase risk of neurotoxicity.