Quality of antimalarial drugs and antibiotics in Papua New Guinea: a survey of the health facility supply chain.
BACKGROUND
Poor-quality life-saving medicines are a major public health threat, particularly in settings with a weak regulatory environment. Insufficient amounts of active pharmaceutical ingredients (API) endanger patient safety and may contribute to the development of drug resistance. In the case of malaria, concerns relate to implications for the efficacy of artemisinin-based combination therapies (ACT). In Papua New Guinea (PNG), Plasmodium falciparum and P. vivax are both endemic and health facilities are the main source of treatment. ACT has been introduced as first-line treatment but other drugs, such as primaquine for the treatment of P. vivax hypnozoites, are widely available. This study investigated the quality of antimalarial drugs and selected antibiotics at all levels of the health facility supply chain in PNG.


RESULTS
Medicines were obtained from randomly sampled health facilities and selected warehouses and hospitals across PNG and analysed for API content using validated high performance liquid chromatography (HPLC). Of 360 tablet/capsule samples from 60 providers, 9.7% (95% CI 6.9, 13.3) contained less, and 0.6% more, API than pharmacopoeial reference ranges, including 29/37 (78.4%) primaquine, 3/70 (4.3%) amodiaquine, and one sample each of quinine, artemether, sulphadoxine-pyrimethamine and amoxicillin. According to the package label, 86.5% of poor-quality samples originated from India. Poor-quality medicines were found in 48.3% of providers at all levels of the supply chain. Drug quality was unrelated to storage conditions.


CONCLUSIONS
This study documents the presence of poor-quality medicines, particularly primaquine, throughout PNG. Primaquine is the only available transmission-blocking antimalarial, likely to become important to prevent the spread of artemisinin-resistant P. falciparum and eliminating P. vivax hypnozoites. The availability of poor-quality medicines reflects the lack of adequate quality control and regulatory mechanisms. Measures to stop the availability of poor-quality medicines should include limiting procurement to WHO prequalified products and implementing routine quality testing.
Papua New Guinea Institute of Medical Research, Goroka, EHP, Papua New Guinea; Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
Manuel W
MW
Hetzel
Curtin University, School of Pharmacy, Perth, WA, Australia.
Madhu
M
Page-Sharp
Central Public Health Laboratory, Boroko, NCD, Papua New Guinea.
Nancy
N
Bala
Papua New Guinea Institute of Medical Research, Goroka, EHP, Papua New Guinea; The University of Queensland, School of Population Health, Herston, QLD, Australia.
Justin
J
Pulford
Papua New Guinea Institute of Medical Research, Madang, MDG, Papua New Guinea.
Inoni
I
Betuela
University of Western Australia, School of Medicine and Pharmacology, Fremantle, WA, Australia.
Timothy M E
TM
Davis
Central Public Health Laboratory, Boroko, NCD, Papua New Guinea.
Evelyn K
EK
Lavu
D000655:Amodiaquine / Q000032:analysis / Q000592:standards / Q000627:therapeutic use; D000658:Amoxicillin / Q000032:analysis / Q000592:standards / Q000627:therapeutic use; D000962:Antimalarials / Q000032:analysis* / Q000592:standards / Q000627:therapeutic use; D000077549:Artemether; D037621:Artemisinins / Q000032:analysis / Q000592:standards / Q000627:therapeutic use; D059451:Biosimilar Pharmaceuticals / Q000032:analysis* / Q000592:standards / Q000627:therapeutic use; D002738:Chloroquine / Q000032:analysis / Q000592:standards / Q000627:therapeutic use; D004351:Drug Resistance; D006268:Health Facilities; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy*; D016780:Malaria, Vivax / Q000188:drug therapy*; D010219:Papua New Guinea; D011319:Primaquine / Q000032:analysis / Q000592:standards / Q000627:therapeutic use; D011786:Quality Control; D011803:Quinine / Q000032:analysis / Q000592:standards / Q000627:therapeutic use
D000962:Antimalarials; D037621:Artemisinins; D059451:Biosimilar Pharmaceuticals; D000655:Amodiaquine; D000658:Amoxicillin; D002738:Chloroquine; C031327:artemisinin; D011803:Quinine; D000077549:Artemether; D011319:Primaquine