Evaluating the quality of antihypertensive drugs in Lagos State, Nigeria.

BACKGROUND: As the burden of noncommunicable diseases grows, access to safe medical therapy is increasing in importance. The aim of this study was to develop a method for evaluating the quality of antihypertensive drugs and to examine whether this prevalence varies by socioeconomic variables.

METHODS: We conducted a cross-sectional survey of registered pharmacies in 6 local government areas (LGAs) in Lagos State, Nigeria. In each LGA, we sampled 17 pharmacies from a list of all registered pharmacies derived from the Pharmacists Council of Nigeria. We assessed drug quality based on (1) the level of active pharmaceutical ingredients (APIs), which identified falsely labeled drug samples; and (2) the amount of impurities, which revealed substandard drug samples in accordance with the international pharmacopoeia guidelines. Good-quality drugs met specifications for both API and impurity.

RESULTS: Of the 102 drug samples collected, 30 (29.3%) were falsely labeled, 76 (74.5%) were substandard,78 (76.5%) were of poor quality and 24 (23.5%) were of good quality.Among the falsely labeled drugs, 2 samples met standards set for purity while 28 did not. Among the 76 substandard drug samples, 28 were also falsely labeled. Of the falsely labeled drugs, 17 (56.7%) came from LGAs with low socioeconomic status, and 40 (52.6%) of the substandard drug samples came from LGAs with high socioeconomic status. Most of the good-quality drug samples, 14 (58.3%), were from LGAs with low socioeconomic status. Eighteen (60%) of the falsely labeled samples, 37 (48.7%) of the substandard samples, and 15 (62.5%) of the good-quality drug samples were from manufacturers based in Asia. The average price was 375.67 Nigerian naira (NGN) for falsely labeled drugs, 383.33 NGN for substandard drugs, and 375.67 NGN for good-quality drugs. The prevalence of falsely labeled and substandard drug samples did not differ by LGA-level socioeconomic status (P = .39) or region of manufacturer (P = .24); however, there was a trend for a difference by price (P = .06).

CONCLUSION: The prevalence of falsely labeled and substandard drug samples was high in Lagos. Treatment of noncommunicable diseases in this setting will require efforts to monitor and assure drug quality.