What is/are Quetiapine?
Quetiapine (/kwɨˈtaɪ.əpiːn/ kwi-TY-ə-peen) (branded as Seroquel, Xeroquel, Ketipinor) is an atypical antipsychotic approved for the treatment of schizophrenia, bipolar disorder, and along with an antidepressant to treat major depressive disorder.
Annual sales are approximately $5.7 billion worldwide, with $2.9 billion in the United States. The U.S. patent, which was set to expire in 2011, received a pediatric exclusivity extension which pushed its expiration to March 26, 2012. The patent has already expired in Canada. There are now several generic versions of quetiapine, such as Quepin, Syquel and Ketipinor.
Quetiapine fumarate is primarily used to treat either schizophrenia or bipolar disorder.
There is tentative evidence of benefit of quetiapine versus placebo in schizophrenia, however definitive conclusions are not possible due to the high rate of people not finishing trials (greater than 50%) and the lack of data on economic outcomes, social functioning or quality of life.
It is debatable whether, as a class, typical or atypical antipsychotics are better. Both have equal drop-out and symptom relapse rates when typicals are used at low to moderate dosages. While quetiapine has lower rates of extrapyramidal side effects, there is greater sleepiness and rates of dry mouth.
In those with bipolar disorder, it is used for depressive episodes, acute manic episodes associated with bipolar I disorder (as either monotherapy or adjunct therapy to lithium, valproate or lamotrigine), and maintenance treatment of bipolar I disorder (as adjunct therapy to lithium or divalproex).
Quetiapine is ineffective in reducing agitation among people with Alzheimer's, whose usage of the drug once constituted 29% of sales. Quetiapine worsens cognitive functioning in the elderly with dementia and therefore is not recommended.
The use of low doses of quetiapine for insomnia, while common, is not recommended, as there is little evidence of benefit and there are concerns regarding adverse effects.
It is sometimes used off-label, often as an augmentation agent, to treat conditions such as obsessive-compulsive disorder, post-traumatic stress disorder, autism, alcoholism, borderline personality disorder, Charles Bonnet Syndrome, depression, Tourette syndrome, musical hallucinations and has been for anxiety disorders.
The most common side-effect of quetiapine is somnolence. Other common side-effects include sluggishness, fatigue, dry mouth, sore throat, dizziness, abdominal pain, constipation, upset stomach, orthostatic hypotension, inflammation or swelling of the sinuses or pharynx, blurred vision, increased appetite, and weight gain. Hypothyroidism has been seen in up to 5% of patients with various effects on levels of TSH, T4 and T3.
Uncommon side effects include bruises, disturbance in speech and language, and/or frightening hallucinations. Mouth ulcers are a rare side effect. Very rare side effects reported were rapid swelling of the skin around the eyes, which increased the appearance of skin ageing.
There is an emerging controversy regarding quetiapine fatalities. The deaths of at least six U.S. military veterans who were given drug cocktails including quetiapine have been attributed to its inclusion by military doctors to treat PTSD. Approximately 10,000 lawsuits against AstraZeneca for problems ranging from slurred speech and chronic insomnia to death have been filed by individuals from civilian populations.
It is marketed as one of the most sedating of all anti-psychotics, although those claims are contested. Beginning users may feel extremely tired and 'out of it' for the first few days, and sometimes longer. Quetiapine's newest indication, for bipolar depression, usually specifically calls for the entire dose to be taken before bedtime due to its sedative effects. The sedative effects may disappear after some time on the drug, or with a change of dosage, and with possibly different, non-sedative side-effects emerging.
Both typical and atypical antipsychotics can cause tardive dyskinesia. According to one study, rates are lower with the atypicals at 3.9% as opposed to the typicals at 5.5%. Although Quetiapine and Clozapine are atypical antipsychotics, switching to these atypicals is an option to minimize symptoms of tardive dyskinesia caused by other atypicals.
Weight gain can be a problem for some patients. When calculated according to a fixed effects model, Quetiapine has been found to cause more weight gain than fluphenazine, haloperidol, loxapine, molindone, olanzapine, pimozide, risperidone, thioridazine, thiothixene, trifluoperazine, and ziprasidone, but less than chlorpromazine, clozapine, perphenazine, and sertindole.
Studies conducted on beagles have resulted in the formation of cataracts. While there are reports of cataracts occurring in humans, controlled studies including thousands of patients have not demonstrated a clear causal association between quetiapine therapy and this side-effect. However, the Seroquel website still recommends users have eye examinations every six months.
As with some other anti-psychotics, quetiapine may lower the seizure threshold, and should be taken with caution in combination with drugs such as bupropion. A recent comparative study of anti-psychotics drugs has found that quetiapine mono treatment was associated with increased risk of death relative to the other analyzed treatments (but still better than no anti-psychotics drug treatment at all).
Quetiapine should be discontinued gradually, with careful consideration from the prescribing doctor, to avoid withdrawal symptoms or relapse.
The British National Formulary recommends a gradual withdrawal when discontinuing anti-psychotic treatment to avoid acute withdrawal syndrome or rapid relapse. Due to compensatory changes at dopamine, serotonin, adrenergic and histamine receptor sites in the central nervous system, withdrawal symptoms can occur during abrupt or over-rapid reduction in dosage. However, despite increasing demand for safe and effective antipsychotic withdrawal protocols or dose-reduction schedules, no specific guidelines with proven safety and efficacy are currently available.
Withdrawal symptoms reported to occur after discontinuation of antipsychotics include nausea, emesis, lightheadedness, diaphoresis, dyskinesia, orthostatic hypotension, tachycardia, insomnia, nervousness, dizziness, headache, excessive non-stop crying, and anxiety. According to Eli Lilly internal documents, discontinuation of atypical neuroleptics similar to seroquel can also cause psoriasis, gingivitis and other inflammatory conditions, dyspepsia, headache, high blood sugar and other health conditions unrelated to psychiatric condition. Some have argued that additional somatic and psychiatric symptoms associated with dopaminergic super-sensitivity, including dyskinesia and acute psychosis, are common features of withdrawal in individuals treated with neuroleptics. This has led some to suggest that the withdrawal process might itself be psychosis-mimetic, producing psychotic-like symptoms even in previously healthy patients, indicating a possible pharmacological origin of mental illness in a yet unknown percentage of patients currently and previously treated with antipsychotics. This question is unresolved, and remains a highly controversial issue among professionals in the medical and mental health communities, as well the public.
Most instances of acute overdosage result only in sedation, hypotension and tachycardia, but cardiac arrythmia, coma and death have occurred in adults. Serum or plasma quetiapine concentrations are usually in the 1–10 mg/L range in overdose survivors, while postmortem blood levels of 10–25 mg/L are generally observed in fatal cases.
Pregnancy and lactation
Pregnancy risk factor C. Drug is toxic to fetus and embryo but have not shown any effect with animals. Long term exposure on infant development is still very unknown, however use in third trimester has risk for abnormal muscle movements and withdrawal symptoms. In newborns, symptoms that may occur are agitation, feeding disorder, hypertonia, hypotonia, respiratory distress, somnolence, and tremor. Hospitalization may be required. During lactation, drug enters breast milk and is not recommended to be taken.
This article uses material from the Wikipedia article Quetiapine, which is released under the Creative Commons Attribution-Share-Alike License 3.0.