Adverse drug reactions: a retrospective review of hospitalized patients at a state psychiatric hospital.

BACKGROUND: There is a paucity of information regarding adverse drug reactions (ADRs) in psychiatric patients. Information on common and preventable ADRs (pADRs) in psychiatric patients will allow for targeted improvement projects. OBJECTIVE: To characterize reported ADRs and pharmacist interventions to prevent ADRs in an extended-care state psychiatric hospital. METHODS: Four years of ADR reports were assessed for probability, reaction severity, pharmacological class of medication involved, preventability, change in therapy, and transfers to a medical facility. The pharmacist intervention database was queried for interventions classified as "prevention of ADR." The interventions were assessed for type of medication and recommendation acceptance. RESULTS: Medication classes responsible for ADRs included mood stabilizers (30%), typical antipsychotics (25%), atypical antipsychotics (25%), and antidepressants (8%). Nine percent resulted in transfer to a medical facility. Of all ADRs, 34.4% were pADRs; mood stabilizers (41%) and atypical antipsychotics (27%) were the most common pADRs. The most common causes of pADRs were supratherapeutic serum concentrations, drug-drug interactions, and history of reaction. There were 87 pharmacist interventions that were classified as "prevention of ADR," and the acceptance rate of pharmacists' recommendations was 96.5%. Mood stabilizers (20%), atypical antipsychotics (17%), and typical antipsychotics (11%) were commonly associated with prevented ADRs. Lithium accounted for 13.8% of prevented ADRs; these ADRs were most often due to a drug-drug interaction with a nonsteroidal anti-inflammatory drug. CONCLUSIONS: ADRs were most commonly associated with mood stabilizers and antipsychotics, and pADRs were common. There is an opportunity to provide education to medical staff on therapeutic drug monitoring and drug-drug interactions for these classes, particularly lithium.