Sexually transmitted infections in Africa: single dose treatment is now affordable.

P rompt treatment of sexually transmitted infections (STIs) with effective antibiotic regimens, preferably contained in a single, supervised dose, is a cornerstone of STI control. The World Health Organization (WHO) revised its treatment guidelines in 2001. A variety of regimens is proposed, from which national control programmes are encouraged to choose, depending on the susceptibility of local strains of Neisseria gonorrhoeae and Haemophilus ducreyi, and on the resources available to pay for treatment. WHO treatment guidelines reflect a tension between, on the one hand, the need to recommend the most effective single dose treatment and, on the other, the fact that this may not be available in many developing countries, especially in sub-Saharan Africa. Third generation cephalosporins, for example, have until recently been prohibitively expensive and, for that reason, are not included in the essential drugs list of some African countries. WHO guidelines have therefore included cheaper alternatives for the treatment of gonorrhoea, such as a 3 day course of co-trimoxazole, which are likely to be very much less efficacious. However, essential drug lists should respond to changing circumstances, and new drugs should be added when this is thought to be cost effective by groups of experts. The price of many drugs has fallen dramatically in sub-Saharan Africa in recent years as a result of the development of a large generic drug industry in developing countries, such as India and China, and a vigorous campaign by WHO and NGOs, such as Médecins sans Frontières (MSF), for better accessibility to essential drugs. Current prices and sources of a number of anti-infective drugs have been publicised in a recent update of a joint UN agencies-MSF document. Table 1 showns drug costs for regimens recommended by WHO, Centers for Disease Control and Prevention (CDC), and UK experts for the most common STIs. 3 4 When recommendations differed we selected the cheapest and/or most convenient. All treatments are to be given orally unless stated otherwise. Prices offered by a supplier may vary according to the quantities ordered, current competition, and other factors, so we conservatively used the median price (number of suppliers varies from two to 16). We also show prices offered by the International Dispensary Association (IDA), which includes additional drugs. To the latter must be added transportation costs and mark ups at various levels of the healthcare system. For the treatment of gonorrhoea, there is no reason to recommend anything other than ciprofloxacin, to which no resistance has been reported so far from Africa, and which cures 99.8% of uncomplicated cases. Ciprofloxacin resistance in N gonorrhoeae emerged in Asia and more recently in parts of the United States and in England and Wales. This needs to be monitored in Africa through surveillance networks, but ciprofloxacin will probably remain very effective for at least a few years as the drug has been little used for indications other than gonorrhoea. Ceftriaxone (99% efficacy) or its oral counterpart cefixime (97%) could be used for pregnant women. 3 There is no obvious reason why spectinomycin, kanamycin or, even worse, cotrimoxazole should continue to be recommended by WHO. A 2 g dose of azithromycin, also recommended by WHO, is more than 20 times more expensive than ciprofloxacin and probably less effective. For the treatment of Chlamydia trachomatis infection, doxycycline is so cheap that it should remain the first line treatment whereas azithromycin could be given to pregnant women. 6 However, for sex workers, a core group having a crucial role in the dissemination of C trachomatis and other sexually transmitted pathogens, azithromycin given under direct observation would guarantee compliance and lead to a 95–100% bacteriological eradication rate. There are two reasons to prefer the ciprofloxacin/doxycycline combination for men with urethral discharge: doxycycline remains substantially cheaper than azithromycin, and there is a lack of data concerning the effectiveness of single dose azithromycin in the treatment of Mycoplasma genitalium—an emerging cause of urethritis in Africa. For women with vaginitis, repeated applications of messy vaginal creams can be forgotten. Topical azoles have a 80–90% efficacy similar to that of oral azoles for the treatment of candidiasis, both of which are superior to nystatin. 9 Generic clotrimazole as a vaginal pessary is available for single dose treatment, but even this convenient approach could be replaced with oral fluconazole, which is now cheaper. For the treatment of trichomoniasis, single dose metronidazole remains the standard drug, 3 4 with 88% efficacy, but single dose tinidazole, used for 30 years, is also recommended by WHO. Tinidazole is only marginally more expensive than metronidazole, better tolerated (less frequent nausea or vomiting), and cures 95% of cases. The only limiting step in overall single dose treatment of vaginitis remains the management of bacterial vaginosis, which causes up to 56–69% of cases of vaginal discharge in non-pregnant Africans. 12 Single dose metronidazole is a second choice, 3 but its effectiveness is somewhat inferior to the 80–90% success obtained with a 7 day course of the same drug. Topical treatments with clindamycin cream or metronidazole gel require 3–7 days of application, are not available as generics, and are less efficacious than oral treatment. 13 Single dose tinidazole offers potential advantages over metronidazole: fewer adverse effects and a longer half life (12–14 hours v 6–7 hours). Contradictory results have been reported in trials of single dose tinidazole in bacterial vaginosis, which used different definitions of disease and of therapeutic success: cure rates of 51–71%, 67–93%, 92%, and 97% were described. Cure rates with single dose metronidazole among HIV infected women with bacterial vaginosis is only half of what is seen in their HIV negative counterparts, and this will need to be kept in mind when designing future trials. In many parts of Africa, an increasing proportion of cases of genital ulcers are caused by herpes simplex, whereas chancroid is much less frequent than 20 years ago, perhaps to some extent because of higher rates of condom use during transactional sex and the widespread use of ciprofloxacin to treat gonorrhoea among core groups. There 432 EDITORIAL