Research Article: Evaluating the quality of antihypertensive drugs in Lagos State, Nigeria

Date Published: February 13, 2019

Publisher: Public Library of Science

Author(s): Elizabeth Thithi Ndichu, Kelechi Ohiri, Oluwafemi Sekoni, Olasunmbo Makinde, Kevin Schulman, Geofrey Musinguzi.


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.

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.

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).

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.

Partial Text

Poor-quality drugs are a global crisis posing a threat to global health and especially the treatment of noncommunicable diseases. Although the deleterious consequences of poor-quality drugs have been described, efforts to control the illicit trade of these drugs are lagging.[1],[2] Addressing the issue of poor-quality medicines is complex and requires coordinated collaboration of industry and government across the supply chain.[1],[3]

Seventeen pharmacies were sampled from each of the six LGAs (Table 2). A total of 102 samples of nifedipine were collected from public and privately owned pharmacies. Of these, 101 (99.0%) were from private pharmacies. All pharmacies were registered with the Pharmaceutical Council of Nigeria. Drug prescriptions were not required for privately owned facilities and were needed only when we sought a drug sample from a state or federal facility. A total of 14 branded drugs were collected from the six LGAs, with each sample packet ranging between 15 and 30 tablets. In most pharmacies, only two branded types were available. The dosage of branded nifedipine collected was 20 mg (n = 94; 92.16%) and 30 mg (n = 8; 7.8%). None were expired at the time of purchase, and all were in blister packages except for one sample that was packed in a transparent resealable plastic bag.

Our report represents the first study of antihypertensive drugs in Lagos State, Nigeria. Of the 102 samples collected, 24 (23.5%) met API and purity standards following biochemical analysis. Although 70.6% of the samples met the standards for label amounts, the levels of impurities in the samples contributed to the large number of poor-quality drugs. A higher proportion of drugs with high levels of impurities came from areas with high socioeconomic status. Contrary to our expectations, a higher number of drugs that met all label amount and purity standards and were of good quality came from areas of low socioeconomic status. Good-quality drugs had a higher mean price compared to low-quality drugs, though the relationship was not significant (P = .29).

In a study of the quality of medications for a noncommunicable disease from retail pharmacies in Lagos State, Nigeria, we found a high prevalence of falsely labeled and substandard samples. The study suggests an urgent need to monitor and assure drug quality for populations across the pharmaceutical supply chain.




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