Basics

Quetiapine is an atypical antipsychotic medication (atypical neuroleptic) used to treat schizophrenia, bipolar disorder, and major depression. Quetiapine acts on both positive and negative symptoms of schizophrenia. It is taken by mouth and requires a prescription.

Pharmacology

Pharmacodynamics

The mechanism of action of quetiapine is not yet fully understood. The antischizophrenic effect probably results from the interaction of the drug with dopamine type 2 (D2) and serotonin 2A (5HT2A) receptors. In bipolar depression and major depression, the effects of quetiapine could be attributed to the binding of this drug or its metabolite to the norepinephrine transporter. Additional effects of quetiapine, including somnolence, orthostatic hypotension, and anticholinergic effects, may result from antagonism of H1 receptors, adrenergic α1-receptors, and muscarinic M1-receptors, respectively.

Pharmacokinetics

The highest plasma concentration of quetiapine occurs 1.5 hours after oral administration. Plasma protein binding of quetiapine is 83%. The major active metabolite of quetiapine is norquetiapine (N-desalkylquetiapine). Quetiapine has an elimination half-life of 6 to 7 hours. Its metabolite, norquetiapine, has a half-life of 9 to 12 hours. Quetiapine is excreted after hepatic metabolism primarily via the kidneys (73%) and in the feces (20%), with the remainder (1%) excreted as the drug in its unmetabolized form.

Toxicity

Side effects

Very common (>10% incidence) adverse effects

dry mouth
Dizziness
Headache
Somnolence (drowsiness; of 15 antipsychotics, quetiapine causes the fifth most sedation. Extended-release (XR) formulations tend to produce less sedation at each dose than immediate-release formulations.)[16]

Common (1-10% incidence) adverse effects.

High blood pressure
Orthostatic hypotension
High pulse rate
Elevated blood cholesterol
Increased serum triglycerides
Abdominal pain
Constipation
Increased appetite
Vomiting
Elevated liver enzymes
Back pain
Asthenia
Insomnia
Lethargy
Tremor
Restlessness
Nasal congestion
Pharyngitis
Fatigue
Pain
Dyspepsia (indigestion)
Peripheral edema
Dysphagia
Weight gain

Rare (<1% incidence) adverse effects

Prolonged QT interval
Sudden cardiac death
Syncope
Diabetic ketoacidosis
Restless legs syndrome
Hyponatremia
Jaundice
Pancreatitis
Agranulocytosis
Leukopenia
Neutropenia
Eosinophilia
Anaphylaxis
Seizure
Hypothyroidism
Myocarditis
Cardiomyopathy
Hepatitis
Suicidal ideation
Priapism
Stevens-Johnson syndrome

Author

Markus Falkenstätter, BSc

Pharmacy student

Markus Falkenstätter is a writer on pharmaceutical topics in Medikamio's medical editorial team. He is in the last semester of his pharmacy studies at the University of Vienna and loves scientific work in the field of natural sciences.

Reviewer

Mag. pharm. Stefanie Brandauer

Pharmacist

Stefanie Lehenauer has been a freelance writer for Medikamio since 2020 and studied pharmacy at the University of Vienna. She works as a pharmacist in Vienna and her passion is herbal medicines and their effects.

Editorial principles

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