Doxycycline for the Prevention of Tick-Borne Relapsing Fever
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《新英格兰医药杂志》
To the Editor: In their article, Hasin et al. (July 13 issue)1 state that a 5-day course of doxycycline is safe and efficacious for the prevention of tick-borne relapsing fever (TBRF) in a person who has been bitten by an infected tick. We dispute both points. Healthy male soldiers, who were the subjects in the study, are not an appropriate population for determining drug safety. General travelers are a more suitable study group for this purpose. A survey of 383 Australian tourists taking doxycycline (100 mg daily) as chemoprophylaxis against malaria found that 15% reported nausea and vomiting, 12% reported diarrhea, and 9% of women reported vaginal itch.2 Other studies have linked doxycycline taken prophylactically with photoallergic rash and with photoonycholysis.3 Adverse drug effects affect compliance and, hence, drug efficacy.4
The safe and effective way to prevent TBRF is to pretreat clothing, including military uniforms, with a synthetic pyrethroid insecticide such as permethrin. Both hard ticks (Ixodidae) and soft ticks (Argasidae) are acutely sensitive to pyrethroids, and all stages of tick in these families will avoid attachment to humans who have sprayed or impregnated their clothing with permethrin.5
Ashley M. Croft, D.T.M.&H.
Headquarters Fifth Division
Shrewsbury SY3 8LZ, United Kingdom
ashley.croft810@land.mod.uk
Christopher J. Jackson, M.B., B.S.
Camp Souter
Kabul BFPO 758, Afghanistan
Alicia H. Darbyshire, M.B., Ch.B.
Headquarters International Security Assistance Force
Kabul BFPO 758, Afghanistan
References
Hasin T, Davidovitch N, Cohen R, et al. Postexposure treatment with doxycycline for the prevention of tick-borne relapsing fever. N Engl J Med 2006;355:148-155.
Phillips MA, Kass RB. User acceptability patterns for mefloquine and doxycycline malaria chemoprophylaxis. J Travel Med 1996;3:40-45.
Passier A, Smits-van Herwaarden A, van Puijenbroek E. Photo-onycholysis associated with the use of doxycycline. BMJ 2004;329:265-265.
Croft AM, Whitehouse DP, Cook GC, Beer MD. Safety evaluation of the drugs available to prevent malaria. Expert Opin Drug Saf 2002;1:19-27.
Evans SR, Korch GW Jr, Lawson MA. Comparative field evaluation of permethrin and deet-treated military uniforms for personal protection against ticks (Acari). J Med Entomol 1990;27:829-834.
The authors reply: The study group was chosen as a relevant population at high risk for exposure to TBRF: healthy young adults who are exposed during army drills or cave visits.1 Our drug-safety data were not meant to be extrapolated to all people taking doxycycline. The survey of Australian tourists2 is of little relevance, since doxycycline was taken for a different indication (prophylaxis against malaria), in a setting that was less suitable for adherence to proper drug ingestion (during travel), and for a much longer duration (2 to 73 days; mean, 27.5). Moreover, the survey was part of a retrospective study without placebo control. In the other study,3 photoonycholysis was reported in five cases, again after prolonged (1 to 4 weeks) treatment with doxycycline, and was linked to excessive exposure to the sun. We agree that permethrin-impregnated clothing for the prevention of tick bites has a great potential for preexposure prophylaxis against TBRF. However, the efficacy and safety of this method have yet to be validated. We see no contradiction in combining an attempt to avoid tick bites using a repellent and giving doxycycline to subjects after suspected tick exposures, when these occur.
Tal Hasin, M.D.
16A Koboby st'
Jerusalem 96757, Israel
hasintal@zahav.net.il
Nadav Davidovitch, M.D., Ph.D.
Ben Gurion University
Beer Sheva 84105, Israel
Dani Cohen, Ph.D.
Tel-Aviv University
Tel Aviv 69978, Israel
References
Sidi G, Davidovitch N, Balicer RD, Anis E, Grotto I, Schwartz E. Tickborne relapsing fever in Israel. Emerg Infect Dis 2005;11:1784-1786.
Phillips MA, Kass RB. User acceptability patterns for mefloquine and doxycycline malaria chemoprophylaxis. J Travel Med 1996;3:40-45.
Passier A, Smits-van Herwaarden A, van Puijenbroek E. Photo-onycholysis associated with the use of doxycycline. BMJ 2004;329:265-265.
The safe and effective way to prevent TBRF is to pretreat clothing, including military uniforms, with a synthetic pyrethroid insecticide such as permethrin. Both hard ticks (Ixodidae) and soft ticks (Argasidae) are acutely sensitive to pyrethroids, and all stages of tick in these families will avoid attachment to humans who have sprayed or impregnated their clothing with permethrin.5
Ashley M. Croft, D.T.M.&H.
Headquarters Fifth Division
Shrewsbury SY3 8LZ, United Kingdom
ashley.croft810@land.mod.uk
Christopher J. Jackson, M.B., B.S.
Camp Souter
Kabul BFPO 758, Afghanistan
Alicia H. Darbyshire, M.B., Ch.B.
Headquarters International Security Assistance Force
Kabul BFPO 758, Afghanistan
References
Hasin T, Davidovitch N, Cohen R, et al. Postexposure treatment with doxycycline for the prevention of tick-borne relapsing fever. N Engl J Med 2006;355:148-155.
Phillips MA, Kass RB. User acceptability patterns for mefloquine and doxycycline malaria chemoprophylaxis. J Travel Med 1996;3:40-45.
Passier A, Smits-van Herwaarden A, van Puijenbroek E. Photo-onycholysis associated with the use of doxycycline. BMJ 2004;329:265-265.
Croft AM, Whitehouse DP, Cook GC, Beer MD. Safety evaluation of the drugs available to prevent malaria. Expert Opin Drug Saf 2002;1:19-27.
Evans SR, Korch GW Jr, Lawson MA. Comparative field evaluation of permethrin and deet-treated military uniforms for personal protection against ticks (Acari). J Med Entomol 1990;27:829-834.
The authors reply: The study group was chosen as a relevant population at high risk for exposure to TBRF: healthy young adults who are exposed during army drills or cave visits.1 Our drug-safety data were not meant to be extrapolated to all people taking doxycycline. The survey of Australian tourists2 is of little relevance, since doxycycline was taken for a different indication (prophylaxis against malaria), in a setting that was less suitable for adherence to proper drug ingestion (during travel), and for a much longer duration (2 to 73 days; mean, 27.5). Moreover, the survey was part of a retrospective study without placebo control. In the other study,3 photoonycholysis was reported in five cases, again after prolonged (1 to 4 weeks) treatment with doxycycline, and was linked to excessive exposure to the sun. We agree that permethrin-impregnated clothing for the prevention of tick bites has a great potential for preexposure prophylaxis against TBRF. However, the efficacy and safety of this method have yet to be validated. We see no contradiction in combining an attempt to avoid tick bites using a repellent and giving doxycycline to subjects after suspected tick exposures, when these occur.
Tal Hasin, M.D.
16A Koboby st'
Jerusalem 96757, Israel
hasintal@zahav.net.il
Nadav Davidovitch, M.D., Ph.D.
Ben Gurion University
Beer Sheva 84105, Israel
Dani Cohen, Ph.D.
Tel-Aviv University
Tel Aviv 69978, Israel
References
Sidi G, Davidovitch N, Balicer RD, Anis E, Grotto I, Schwartz E. Tickborne relapsing fever in Israel. Emerg Infect Dis 2005;11:1784-1786.
Phillips MA, Kass RB. User acceptability patterns for mefloquine and doxycycline malaria chemoprophylaxis. J Travel Med 1996;3:40-45.
Passier A, Smits-van Herwaarden A, van Puijenbroek E. Photo-onycholysis associated with the use of doxycycline. BMJ 2004;329:265-265.