Hypersensitivity trimethoprim-sulfamethoxazole

Trimethoprim-sulfamethoxazole is used frequently for preventive or active treatment of Pneumocystis carinii pneumonia in patients with the AIDS. Adverse reactions to trimethoprim-sulfamethoxazole have been observed to occur much more frequently in these patients compared with those without AIDS. Adverse effects to trimethoprim-sulfamethoxazole occur in 50% to 80% of AIDS patients compared with 10% of other immunocompromised patients. Trimethoprim-sulfamethoxazole was associated with an adverse-event rate of 26.3 per 100 person-years and hypersensitivity events at 22 per 100 person-years. Adverse-event rate was related to lower CD4+ cell count. When the CD4+ cell count was less than 100/mm , the adverse drug event rate was 31 per 100 person-years. ... 

Immediate-type hypersensitivity Clarithromycin or azithromycin or trimethoprim-sulfamethoxazole Non immediate-type hypersensitivity / -Lactamase-stable cephalosporin High-dose amoxicillin with clavulanate or / -lactamase-stable cephalosporin... 

Patients with AIDS frequently have hypersensitivity reactions to trimethoprim-sulfamethoxazole, including rash, neutropenia, Stevens-Johnson syndrome. Sweet s syndrome, and pulmonary infiltrates. It may be possible to continue therapy in such patients following rapid oral desensitization. 

Rubinstein A (1979) LE like disease caused by nalidixin acid. N Engl J Med 301 1288 Russell A, Lessof M (1971) Hypersensitivity to drugs. Clin Allergy 1 179 Salter A (1973) The toxicity profile of trimethoprim-sulfamethoxazole after four years of widerspread use. Med J Aust [Spec Suppl] 1 70 Saslaw S, Klainer AS (1969) Rheumatoid syndrome during isoniazid therapy. Am Rev Re-spir Dis 100 221... 

One of the most common infections in man is caused by the protozoan, Toxoplasma gondii, which is transmitted to humans when they consume raw or inadequately cooked, infected meat. Infected pregnant women can transmit the organism to the fetus. Cats are the only animals that shed oocysts that can infect other animals as well as man. The treatment of choice for this condition is the antifolate drug, pyrimethamine [peer i METH a meen] (see p. 353). A combination of sulfadiazine (see p. 289) and pyrimethamine is also efficacious. Leucovorin is often administered to protect against folate deficiency. Other inhibitors of folate biosynthesis, such as trimethoprim (see p. 293) and sulfamethoxazole (see p. 289) are without therapeutic efficacy in toxoplasmosis. [Note At the first appearance of a rash, pyrimethamine should be discontinued since hypersensitivity to this drug can be severe.]... 

Caumes E, Guermonprez G, Lecomte C, et al. Efficacy and safety of desensitization with sulfamethoxazole and trimethoprim in 48 previously hypersensitive patients infected with human immunodeficiency virus. Arch Dermatol 1997 133 465 69. 

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