Cariprazine

BRAND NAMES

Cariprazine is marketed under several brand names, including

 Vraylar in the United States and

 Reagila in Europe and other regions.

MECHANISM OF ACTION

Cariprazine works by balancing dopamine and serotonin activity in the brain, which helps reduce psychotic symptoms and stabilize mood.

PHARMACOKINETICS

Absorption

Cariprazine is well absorbed orally, with peak blood levels typically reached 3 to 6 hours after a dose

Distribution

Cariprazine has a large volume of distribution (Vd) of approximately 20–25 L/kg, indicating it distributes extensively into body tissues, including the brain, where it exerts its therapeutic effects.

Metabolism

Cariprazine is primarily metabolized in the liver by the cytochrome P450 enzyme CYP3A4, with a minor contribution from CYP2D6. It is converted into two major active metabolites, desmethyl-cariprazine and didesmethyl-cariprazine, which also contribute to its therapeutic effects and prolong its overall activity in the body.

Excretion

Cariprazine and its metabolites are mainly excreted through feces (≈60%) and urine (≈30%), with a long elimination half-life due to its active metabolites.

PHARMACODYNAMICS

Cariprazine’s pharmacodynamics involve partial agonism at dopamine D3 and D2 receptors and serotonin 5-HT1A receptors, along with antagonism at 5-HT2B receptors. This receptor activity helps reduce psychotic symptoms, stabilize mood, and improve cognitive function in schizophrenia and bipolar disorder.

ADMINISTRATION

Cariprazine is administered orally in tablet form, usually once daily, with or without food, as prescribed by a healthcare provider.

DOSAGE AND STRENGTH

The typical starting dose is 1.5 mg once daily, which may be gradually increased based on the patient’s response and tolerability, up to a maximum of6 mg per day.

FOOD INTERACTIONS

Cariprazine can be taken with or without food, as its absorption is not significantly affected by meals. No major food interactions have been reported.

DRUG INTERACTIONS

• CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) can increase cariprazine levels, raising the risk of side effects.

• CYP3A4 inducers (e.g., rifampin, carbamazepine) can decrease cariprazine levels, reducing its effectiveness.

• Other CNS-active drugs (e.g., antipsychotics, antidepressants, sedatives) may enhance side effects like drowsiness, dizziness, or QT prolongation

 CONTRAINDICATIONS

• Known hypersensitivity to cariprazine or any tablet components.

• Severe liver impairment (Child-Pugh class C), as metabolism may be significantly affected.

• Concomitant use with strong CYP3A4 inhibitors or inducers without proper dose adjustment.

SIDE EFFECTS

• Extrapyramidal symptoms (tremor, restlessness, involuntary movements)

• Akathisia (inner restlessness)

• Insomnia

• Nausea and vomiting

• Constipation

• Dizziness

OVERDOSE

Cariprazine overdose can cause drowsiness, agitation, tremors, low bloodpressure, and heart rhythm problems. Treatment is supportive, focusing on monitoring vital signs and managing symptoms, and requires immediate medical attention.

TOXICITY

Cariprazine toxicity may result in excessive sedation, severe movement disorders, low blood pressure, and cardiac abnormalities. Long-term or high-dose toxicity can also affect metabolism and organ function, so careful dosing and monitoring are essential.