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