A total of 579 references remained after duplicates were removed. A search of the . Food and Drug Administration website and labels of approved products were reviewed. A marked decline in the effectiveness of permethrin and synergized pyrethrins was found, probably because of resistance arising from widespread and indiscriminate use, and the emergence of knockdown resistance mutations. The potential toxicity of lindane in the setting of readily available, safer, and more effective alternatives, should limit its use. Prescription products shown to be safe and effective with a single application, without nit combing, are topical ivermectin, malathion, and spinosad, whereas benzyl alcohol requires two applications. Home remedies such as mayonnaise, and essential oils, have not been demonstrated to be safe or effective, and may carry potential for severe adverse events. The high risk of failure of over-the-counter treatments in eliminating head louse infestations drives a need for health care provider recognition of the limitations of current treatments and for judicious use of treatments that remain effective.
The 20 th Essential Medicines List, published on 6 June 2017, marks the 40th anniversary of this flagship WHO tool to expand access to medicines. The updated list adds 30 medicines for adults and 25 for children, and specifies new uses for 9 already-listed products, bringing the total to 433 drugs deemed essential for addressing the most important public health needs globally. The 20 th List also provides new advice on which antibiotics to use for common infections and which to preserve for the most serious syndromes, based on a thorough review of all essential antibiotics. The aim is to optimise antibiotic use and reduce antibiotic resistance without restricting access. Other important additions include medicines for HIV, hepatitis C, tuberculosis and cancer.