Quetiapine (Dosage)

Quetiapine is an atypical antipsychotic used in the treatment of schizophrenia and manic and depressive episodes of bipolar disorder.

ACTION MECHANISM

Quetiapine interacts with a wide range of neurotransmitter receptors. It has affinity for cerebral serotonin (5-HT2) and D1 / D2 dopamine receptors, as well as alpha 1 adrenergic and histaminergic, alpha 2 adrenergic and 5HT1A serotonin receptors.

Quetiapine has a similar efficacy to other neuroleptics on positive psychotic symptoms; it is also effective on persistent positive symptoms (although there are no comparative data with clozapine).

Extrapyramidal side effects are less intense than those of classic antipsychotics, but there is a higher incidence of metabolic effects.

SIDE EFFECTS

Somnolence, dizziness, asthenia, orthostatic hypotension and syncope (especially when initiating therapy). Gastrointestinal symptoms, constipation, dry mouth, elevated liver enzymes, hyperglycemia, weight gain, seizures, neuroleptic malignant syndrome, slight decrease in total T4 and free T4, extrapyramidal symptoms, early or late dyskinesia, akathisia.

CONTRAINDICATIONS

Hypersensitivity to quetiapine. Avoid concomitancy with cytochrome P450 3A4 inhibitors (such as HIV protease inhibitors, azole antifungals, erythromycin, clarithromycin and nefazodone).

PHARMACOLOGIC INTERACTIONS

Caution when prescribed with other centrally acting drugs and alcohol.

Inhibitors of cytochrome P450 3A4 (ketoconazole, itraconazole, erythromycin, clarithromycin, grapefruit juice, antiretroviral protease inhibitors, nefazone, etc.) may increase quetiapine levels: avoid their use together.

Phenytoin, carbamazepine, rifampicin, and thioridazine may decrease quetiapine levels.

Quetiapine increases its clearance with: carbamazepine, phenytoin and thioridazine.

BRAND NAMES

• Ilufren ®
• Psicotric ®
• Qudix ®
• Quentiax ®
• Quentiamylan ®
• Rocoz ®
• Seroquel ®