Phenobarbital remains one of the most widely used
antiepileptic drugs worldwide, yet there are limited data regarding side effects associated with its use in routine clinical care settings in low-income countries. Available data suggests that
phenobarbital is as effective as other first-line drugs for treating
tonic-clonic seizures, but side effect reports differ widely between high and low-income settings. A better understanding of
phenobarbital side effect profile and severity in low-income settings is warranted given its role in efforts to decrease the
epilepsy treatment gap. We used the Liverpool adverse events profile (LEAP) to assess side effects in consecutive patients with
epilepsy on
phenobarbital seeking care in rural Zambia. Data regarding age, gender, medication dose, and medication adherence were also collected. T-tests and Spearman's correlation coefficient were used to assess predictors of LEAP score and medication adherence. Thirty-five patients receiving a mean dose of 2.1mg/kg/day (SD: 2.78 mg/kg/day) of
phenobarbital were assessed. All participants reported at least one side effect in the previous four weeks with a median of 6 symptoms (IQR: 4-8) and a mean side effects score of 28/76 (SD: 5.38). Over half reported
sleepiness and
dizziness. Memory problems and depression were also common (both 46%). Total LAEP score was not associated with age (p=0.88), gender (p=0.17), or
phenobarbital dose (p=0.13). Medication adherence was not associated with side effects total score (p=0.56). Rural Zambian adults taking
phenobarbital at doses recommended by the World Health Organization report a significant number of side effects. The most common side effects reported were similar to those reported in high-income countries. The significant burden of
phenobarbital-associated side effects in this African cohort is in contrast to data from non-randomized clinical trials in China that reported
phenobarbital to be well-tolerated with few side effects. Additional investigations regarding
phenobarbital side effects during routine care in low income settings is warranted.