title: Reversible parkinsonism and cognitive decline due to a possible interaction of valproic acid and quetiapine.
abstract: OBJECTIVE
  Combination therapy with valproic acid plus quetiapine is recommended as one of the first-line approaches to treatment of manic or mixed episodes in patients with bipolar disorder.
  
  
  METHODS
  A 66-year-old patient with this psychiatric disease developed parkinsonism and cognitive decline during concomitant treatment with both drugs. The rapid onset of symptoms soon after use of the combination suggested an interaction/using the Karch-Lasagna criteria, the interaction was judged to be definite.
  
  
  CONCLUSIONS
  Their evidence on a pharmacokinetic drug interaction between the two drugs is conflicting but possible underlying mechanisms proposed include CYP3A4 inhibition. As concomitant use of valproate and quetiapine is now quite frequent in bipolar disorder, this potential interaction should be closely monitored, especially in the elderly.
authors.affiliation: Department of Psychiatry, Hospital Universitario La Paz, Madrid, Spain. cdios.scsm@salud.madrid.org
authors.forename: C
authors.initials: C
authors.lastname: De Dios
authors.forename: S
authors.initials: S
authors.lastname: Fudio
authors.forename: A
authors.initials: A
authors.lastname: Lorenzo
mesh_terms: D000368:Aged; D018692:Antimanic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy; D003072:Cognition Disorders / Q000139:chemically induced*; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D003987:Dibenzothiazepines / Q000009:adverse effects* / Q000627:therapeutic use; D004347:Drug Interactions; D016903:Drug Monitoring; D004359:Drug Therapy, Combination / Q000009:adverse effects; D005260:Female; D006801:Humans; D010302:Parkinson Disease, Secondary / Q000139:chemically induced*; D000069348:Quetiapine Fumarate; D016896:Treatment Outcome; D014635:Valproic Acid / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D018692:Antimanic Agents; D003987:Dibenzothiazepines; D000069348:Quetiapine Fumarate; D014635:Valproic Acid; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human