Antipsychotic Medications Anti-psychotic Drugs quetiapine, Seroquel

Antipsychotic: quetiapine, Seroquel

Generic Name: quetiapine
Brand Name(s): Seroquel
Common Use: Antipsychotic

Quetiapine, a dibenzothiazepine derivative, is an antipsychotic agent which interacts with a broad range of neurotransmitters.

Quetiapine is indicated for the management of the manifestations of schizophrenia. The antipsychotic efficacy of quetiapine was established in short-term (6 week) controlled inpatient trials (see Clinical Pharmacology). The efficacy of quetiapine in long term use, that is, for more than 6 weeks, has not been systematically evaluated in controlled trials.

Contraindications

Quetiapine is contraindicated in patients with a known hypersensitivity to this medication or any of its ingredients.

Adverse Reactions

The stated frequencies of adverse events represent the proportion of individuals who experienced, at least once, a treatment-emergent adverse event of the type listed. An event was considered treatment-emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation.
The prescriber should be aware that the figures in the tables and tabulations cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those that prevailed in the clinical trials. Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses, and investigators. The figures cited, however, do provide the prescribing physician with some basis for estimating the relative contribution of drug and nondrug factors to the side effect incidence in the populations studied.
Commonly Observed Adverse Events in Short-term Trials:
The following treatment-emergent adverse events commonly occurred during acute therapy with quetiapine (incidence of at least 5%, and an incidence at least 5% higher than that observed with placebo): somnolence, dizziness, dry mouth, postural hypotension, and elevated ALT (SGPT) levels.

Adverse Events Associated with Discontinuation:
Short-Term, Placebo-Controlled Clinical Trials:
Overall, 3.9% of quetiapine-treated patients discontinued treatment due to adverse events compared with 2.9% of placebo-treated patients. Somnolence, the single most common adverse event leading to withdrawal from quetiapine treatment, led to the withdrawal of four quetiapine-treated patients and no placebo-treated patients. Postural hypotension, hypotension, and/or tachycardia led to withdrawal of 1.8% of quetiapine-treated subjects, compared to 0.5% of placebo-treated subjects.

Combined Short-and Long-term Controlled Trial Database:
In a premarketing controlled clinical trial database of 1710 quetiapine-treated patients, 5% discontinued due to an adverse event. Somnolence was the single most common adverse event leading to withdrawal of 24 patients from quetiapine, and was the only adverse event leading to withdrawal that occurred in more than 1% of patients. Cardiovascular adverse events (e.g., postural hypotension, hypotension, tachycardia, dizziness) accounted for 20% of all subject withdrawals from quetiapine treatment. Sixteen (0.9%) quetiapine-treated subjects were withdrawn due to elevated liver enzymes. Four quetiapine-treated subjects were withdrawn because of leukopenia. Two of these subjects had at least one clinically significant, non-baseline low neutrophil count. Two quetiapine-treated subjects were withdraw from the trial because of suspected neuroleptic malignant syndrome (NMS).

Weight Gain:
As with other antipsychotics, quetiapine may be associated with weight gain. During acute therapy (up to 6 weeks) in placebo-controlled clinical trials, mean weight gain in patients taking quetiapine was 2.3 kilograms compared to a mean weight gain of 0.1 kilograms in patients taking placebo. In long-term trials average weight gain was 5.6 kilograms after one year of treatment.

Overdose

In clinical trials, experience with quetiapine in overdosage is limited. Doses in excess of 10 g have been taken; no fatalities were reported and patients recovered without sequelae. In general, reported signs and symptoms were those resulting from an exaggeration of the drug's known pharmacological effects e.g., drowsiness and sedation, tachycardia and hypotension.Treatment

There is no specific antidote to quetiapine. In cases of severe intoxication, the possibility of multiple drug involvement should be considered, and intensive care procedures are recommended, including establishing and maintaining a patent airway, ensuring adequate oxygenation and ventilation, and monitoring and support of the cardiovascular system.Close medical supervision and monitoring should be continued until the patient recovers.

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