Reactions 708 - 4 Jul 1998

Probenecid

Hypersensitivity: case reportA 48-year-old man with HIV infection developed a

cutaneous hypersensitivity reaction to probenecid duringtreatment with a combination regimen of probenecid andcidofovir for a recurrence of peri-anal herpes simplex type 2infection. Probenecid was given in combination with cidofovirin order to decrease the concentration of cidofovir in the urine,since cidofovir alone may cause renal toxicity.

The patient tolerated 5 treatments of the cidofovir plusprobenecid regimen, but his renal function then deteriorated,necessitating discontinuation of all his medications. However,1 week later, the man mistakenly took probenecid 2g anddeveloped generalised urticaria 1 hour later. His skin rashresolved 1 hour after he received diphenhydramine. Twoweeks later, he accidentally ingested probenecid [dose notstated] again and developed the same skin reaction within 30minutes. He was again treated with antihistamines and hissymptoms resolved rapidly.

Since the patient had initially had a good response to thecidofovir plus probenecid regimen, a second trial was initiated.He was premedicated with prednisone, cimetidine anddiphenhydramine prior to probenecid treatment and was ableto tolerate 3 further treatments with cidofovir plus probenecid.

Author comment: ‘It appears that probenecid can be addedto the growing list of medications associated with an increasedincidence of adverse reactions in the AIDS population.’Myers KW, et al. Probenecid hypersensitivity in AIDS: a case report. Annals ofAllergy, Asthma and Immunology 80: 416-418, May 1998 - USA 800681659

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Reactions 4 Jul 1998 No. 7080114-9954/10/0708-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved