Quetiapine

Aka: Quetiapine, Seroquel

1. Class
   1. Atypical Antipsychotic (Second Generation agent)
   2. Neuroleptic
   3. Dibenzothiazepine Antipsychotic
2. Mechanism
   1. Dopamine, Serotonin, histamine and adrenergic antagonist
3. Indications
   1. Schizophrenia
   2. Psychosis in Dementia
   3. Mania (not FDA approved)
   4. Bipolar Disorder (not FDA approved)
   5. Autism (not FDA approved)
   6. Insomnia (not FDA approved)
4. Dosing
   1. Adults
      1. Initial: 25 mg PO bid-tid
      2. Increase in 25-50 mg/day increments
      3. Target: 300-400 mg/day divided bid-tid
      4. Maximum dose: 750 mg/day
   2. Elderly
      1. Initial dose: 12.5 mg PO qhs
      2. Titrate up every few days (caution due to sedation)
5. Adverse Effects: General
   1. Sedation
   2. Headache
   3. Orthostatic Hypotension
   4. Cataract formation
   5. Dry Mouth
   6. Weight gain
   7. Neuroleptic Malignant Syndrome
   8. QTc Prolongation
6. Adverse Effects: Overdose
   1. Somnolence
   2. Tachycardia
   3. Hypotension
7. Drug Interactions
   1. Increase Antipsychotic levels (toxicity risk): Monitor for toxicity
      1. Clarithromycin
      2. Erythromycin
      3. Grapefruit juice
      4. Fluconazole
      5. Itraconazole
      6. Ketoconazole
      7. Quinidine
   2. Decrease Antipsychotic levels (lower efficacy)
      1. Barbiturates
      2. Carbamazepine
      3. Phenytoin
      4. Rifampin
      5. Theophylline
   3. Other effects
      1. Avoid concurrent use of other medications prolonging QT Interval
         1. See Prolonged QT Interval due to Medication
8. Monitoring
   1. See Antipsychotic
   2. Screen for Cataract formation every 6 months
   3. Consider EKG, Electrolyte and Magnesium monitoring due to QT Interval prolongation risk
9. Pharmacokinetics
   1. Metabolized by Cytochrome P450 3A4