Ketilept Retard (Quetiapine Fumarate)

Ketilept Retard (quetiapine) is used in psychiatric disorders that involve dopamine and serotonin dysregulation.

• Schizophrenia: reduces positive and negative symptoms, improving overall functioning.
• Bipolar disorder: stabilizes mood during manic and depressive episodes.
• Major depressive disorder (adjunct): enhances antidepressant response when added to standard therapy.

• Quetiapine acts as an antagonist at dopamine D2 and serotonin 5‑HT2A receptors, while also modulating activity at histamine H1, adrenergic α1 and muscarinic receptors. This receptor profile reduces dopaminergic transmission in mesolimbic pathways and balances serotonergic signaling, contributing to antipsychotic, mood‑stabilising and antidepressant effects. The combined antagonism leads to decreased psychotic symptoms, mood stabilization, and improvement of depressive symptoms, while the antihistaminic and anticholinergic actions contribute to sedation and metabolic effects.

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

Common Side Effects

• Drowsiness or sedation
• Dizziness or light‑headedness
• Dry mouth
• Constipation
• Weight gain or increased appetite
• Orthostatic hypotension
• Elevated cholesterol

Serious or Rare Side Effects

• Neuroleptic malignant syndrome
• Agranulocytosis or severe neutropenia
• Tardive dyskinesia or other movement disorders
• Suicidal thoughts or behaviors, especially early in treatment
• Severe hypotension
• Myocarditis

When prescribing Ketilept Retard, clinicians should observe several precautionary measures to ensure safe use.

• Dose titration: start with a low dose and increase gradually based on response.
• Metabolic monitoring: regularly assess weight, fasting glucose and lipid profile.
• Suicidality assessment: evaluate for suicidal thoughts, particularly during initial treatment.
• Discontinuation: avoid abrupt cessation to reduce risk of withdrawal or rebound symptoms.
• Pregnancy and lactation: prescribe only if potential benefits outweigh potential risks.
• Store at ambient temperature: keep in original packaging, protect from moisture and heat.

Quetiapine's metabolism and central nervous system effects lead to several clinically relevant drug interactions.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may markedly increase quetiapine plasma concentrations.
• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may substantially reduce quetiapine levels.
• CNS depressants (alcohol, benzodiazepines, opioids): additive sedation and respiratory depression.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents: enhanced hypotensive effect.
• Antidiabetic medications: possible alteration of glucose control.
• Other antipsychotics or serotonergic drugs: increased risk of QT prolongation and extrapyramidal symptoms.