November 1990

Increased Prescribing of Antidepressants Subsequent to ß-Blocker Therapy

Author Affiliations

From the College of Pharmacy (Drs Wallace and Blackburn, and Ms Thiessen) and Department of Pharmacology, College of Medicine (Dr Wilson), University of Saskatchewan, Saskatoon, and Department of Clinical Pharmacology, Karolinska Institute, Huddinge, Sweden (Dr Bergman). Ms Thiessen is now with the Pharmacy (Clinical Services), St Paul's Hospital, Sasakatoon.

Arch Intern Med. 1990;150(11):2286-2290. doi:10.1001/archinte.1990.00390220044009

• Using records of the Saskatchewan Prescription Drug Plan, we determined the incidence of antidepressant use (a marker for depressive symptoms) in patients who received β-blockers or other treatments for chronic diseases (diuretics, antihypertensives, and hypoglycemics) during 1984, but not in the previous 6 months. Antidepressants initiated within 12 months after the study drug were counted. Of the 3218 new β-blocker users, 6.4% received concurrent prescriptions (ie, within 34 days) for an antidepressant and β-blocker. Only 2.8% of the reference group (no study drug use) received an antidepressant. A greater proportion of patients prescribed propranolol (9.5%) received an antidepressant than those prescribed other "lipophilic" (3.9%) or "hydrophilic" (2.5%) β-blockers. Incidence ratios for propranolol revealed the overall risk antidepressant use was 4.8 (95% confidence interval [Cl], 4.1 to 5.5) times that of the reference group and 2.1 (95% Cl, 1.7 to 2.5) times that of all other study drug users. For propranolol, relative risk of antidepressant use (drug/reference group) varied with age and was greatest in the 20- to 39-year-old group (17.2; 95% Cl, 13.7 to 21.5).

(Arch Intern Med. 1990;150:2286-2290)