Quetiapine: Difference between revisions

| halflife          = ~6 h (parent compound, immediate-release); ~9-12 h (active metabolite N-desalkylquetiapine, also called norquetiapine)

| bioavailability  = Tablet ~100% relative to oral solution; extensive first-pass metabolism

| legal            = [[USLegal:Prescription only|Prescription only]]; not a controlled substance

| mechanism        = Dopamine D2 and serotonin 5-HT2A receptor antagonist<ref name="quet-mech">S1</ref> <vote slug="atypical-claim-quet">Quetiapine acts as an antagonist at dopamine D2 and serotonin 5-HT2A receptors and has substantial activity at histaminergic, adrenergic, and other receptors that contribute to its clinical effects.</vote>

| pregnancy_details = Quetiapine crosses the placenta in modest amounts (umbilical cord-to-maternal plasma ratio approximately 24%, lower than risperidone or olanzapine).<ref name="newport2007">Newport DJ, Calamaras MR, DeVane CL, Donovan J, Beach AJ, Winn S, Knight BT, Gibson BB, Viguera AC, Owens MJ, Nemeroff CB, Stowe ZN. Atypical antipsychotic administration during late pregnancy: placental passage and obstetrical outcomes. American Journal of Psychiatry. 2007;164(8):1214-1220. PMID: 17671284.</ref> The pregnancy literature on atypical neuroleptics has substantially attenuated earlier concerns about teratogenicity; recent large cohort analyses using active-comparator designs and confounding-by-indication adjustment have found no consistent signal for major congenital malformations with quetiapine specifically.<ref name="huybrechts2016">Huybrechts KF, Hernandez-Diaz S, Patorno E, Desai RJ, Mogun H, Dejene SZ, Cohen JM, Panchaud A, Cohen L, Bateman BT. Antipsychotic use in pregnancy and the risk for congenital malformations. JAMA Psychiatry. 2016;73(9):938-946. PMID: 27540849.</ref> Quetiapine is therefore frequently used in pregnancy when neuroleptic treatment is clinically necessary, both for primary indications such as bipolar disorder and schizophrenia and as a substitute for higher-risk medicines such as [[Valproic acid|valproate]].

For women with bipolar disorder or schizophrenia maintained on quetiapine who become pregnant, continuation is generally preferred to discontinuation because of relapse risk; the medicine's relative safety profile in pregnancy makes the maternal mental health argument straightforward. For women on quetiapine off-label for sleep or anxiety, pregnancy is an appropriate occasion to deprescribe in favor of behavioral interventions or, where pharmacotherapy is required, evidence-based alternatives such as the SSRI [[Sertraline|sertraline]].

Management is primarily supportive: airway protection, intravenous fluids for hypotension, ECG monitoring with attention to QT and arrhythmias, cardiac monitoring for at least 24 hours in significant ingestions. [[Activated charcoal|Activated charcoal]] may be considered within one hour of ingestion if the airway is protected. [[:Category:Vasopressors|Vasopressors]] ([[Norepinephrine (medication)|norepinephrine]] preferred over [[Dopamine (medication)|dopamine]], given quetiapine's alpha-1 antagonism) for refractory hypotension. There is no specific antidote. [[Hemodialysis|Hemodialysis]] is not effective owing to the large volume of distribution.

| counseling        = '''Off-label use: most quetiapine prescriptions are for indications the medicine is not formally approved to treat.''' If quetiapine has been prescribed for sleep, anxiety, agitation, or PTSD, the patient should understand that the prescribing is off-label, that the evidence base for these indications is modest, that the metabolic and cardiovascular risk profile applies even at low doses, and that evidence-based alternatives exist ([[Cognitive behavioral therapy for insomnia|cognitive behavioral therapy for insomnia]], SSRIs and SNRIs for anxiety, exposure-based therapies for PTSD).

[[Category:Neuroleptics]]

[[Category:Second-generation neuroleptics]]

[[Category:Medicines]]