Table 2.

Association between antibiotic use and hospitalization for phenytoin toxicity

Antibiotic	Patients Cases n (%) (n = 796)	Controls n (%) (n = 3148)	Crude odds ratio (95% confidence interval)	Adjusted odds ratio† (95% confidence interval)
TMP/SMX	25 (3.1)	47 (1.5)	2.18 (1.33, 3.57)	2.11 (1.24, 3.60)
Amoxicillin	25 (3.1)	61 (1.9)	1.14 (0.66, 1.96)	1.12 (0.64, 1.98)

TMP/SMX, trimethoprim-sulfamethoxazole.

^†Adjusted for age category, hospitalization for phenytoin toxicity in previous year, chronic disease (malignancy, hepatic, renal, alcoholism), income quintile, living in long-term care facility, number of prescription drugs in previous year, number of years of phenytoin treatment, and interacting medications (Appendix 1).