SEROQUEL
DESCRIPTION / DEFINITIONS: Seroquel® (quetiapine fumarate) is a atypical antipsychotic. Seroquel is a drug prescribed for the treatment of schizophrenia and the treatment of bipolar depression and mania.
ADDICTION / DEPENDENCE: Half life and metabolism, Black Box Warning.
SIDE EFFECTS: Anxiety, agitation, panic attacks, insomnia (see list below).
WITHDRAWAL SYMPTOMS: Nausea, vomiting and insomnia (see list below).
TREATMENT: Medical detoxification.
DESCRIPTION / DEFINITIONS
Seroquel (quetiapine fumarate) is prescribed for the treatment of schizophrenia, bipolar depression and mania. According to its label, “The mechanism of action of Seroquel, as with other drugs having efficacy in the treatment of schizophrenia and bipolar disorder, is unknown. However, it has been proposed that the efficacy of SEROQUEL in schizophrenia and its mood stabilizing properties in bipolar depression and mania are mediated through a combination of dopamine type 2 (D2) and serotonin type 2 (5HT2) antagonism.”
ADDICTION / DEPENDENCE
HALF LIFE AND METABOLISM
The biological half life of a substance is the time it takes for a drug to lose half of its pharmacologic activity. This is significant because it affects how soon withdrawal symptoms may appear.
The half life of Seroquel is approximately 5 hours.
Seroquel is mainly metabolized through the P450 pathway in the liver and the enzyme primarily handling the metabolism is CYP3A4.
The CYP enzymes are the major enzymes involved in drug metabolism, and since many drugs may increase or decrease the activity of various CYP isozymes, this is a major source of adverse drug interactions, since changes in CYP enzyme activity may affect the metabolism and clearance of various drugs. For example, if one drug inhibits the CYP-mediated metabolism of another drug, the second drug may accumulate within the body to toxic levels, possibly causing an overdose.
BLACK BOX WARNING
The Food and Drug Administration (FDA) has decided that some drugs pose very serious risks and have required these drugs have what is called a black box warning. Zyprexa has a black box warning. Here is the warning.
Increased Mortality in Elderly Patients with Dementia-Related Psychosis
Elderly patients with dementia-related psychosis treated with atypical antipsychotic drugs are at an increased risk of death compared to placebo. Analyses of seventeen placebo-controlled trials (modal duration of 10 weeks) in these patients revealed a risk of death in the drug-treated patients of between 1.6 to 1.7 times that seen in placebo-treated patients. Over the course of a typical 10 week controlled trial, the rate of death in drug-treated patients was about 4.5%, compared to a rate of about 2.6% in the placebo group. Although the causes of death were varied, most of the deaths appeared to be either cardiovascular (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature. SEROQUEL (quetiapine) is not approved for the treatment of patients with Dementia-Related Psychosis.
Suicidality and Antidepressant Drugs
Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of SEROQUEL or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. SEROQUEL is not approved for use in pediatric patients. (See
Warnings: Clinical Worsening and Suicide Risk,
Precautions: Information for Patients, and
Precautions: Pediatric Use).
SIDE EFFECTS
The following information is taken from the Seroquel label:
WITHDRAWAL SYMPTOMS
Seroquel can be a very difficult drug to stop taking.
- agitation
- anorexia
- anxiety
- diarrhea
- emesis (vomiting)
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- insomnia
- itching
- muscle pain
- nausea
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- restlessness
- rhinorrhoea (runny nose)
- sweating
- vomiting
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TREATMENT
Withdrawal from Seroquel should only be done under the care of a health practitioner. The safest way is to withdraw at an inpatient medical detox facility. At an inpatient medical detox facility with a protocol that includes hydration, vitamins and supplements, most patients can safely stop taking Seroquel in about seven days. Patients can withdraw from Seroquel on an outpatient basis but it will normally take at least four weeks.
