Theophylline and Antiparasitic Drug Interactions
Mebendazole and thiabendazole are benzimidazole compounds used in the treatment of parasitic infections. Patients with asthma who have immigrated from areas endemic with Strongyloides may have exacerbations of their asthma with Strongyloides migration up the tracheobronchial tree. These patients may be treated with theophylline and if Strongyloides is found in stool or sputum specimens, thiabendazole may be added to their treatment.
There have been two well documented cases of a theophylline-thiabendazole interaction. In the first case, the theophylline concentration rose from 105 ltmol/L (19 |xg/ml) to 255 jimol/L (46 ^g/ml) during thiabendazole therapy. Toxic theophylline concentrations were avoided in the second case by reducing the theophylline dose by 33 percent initially, then again to 50 percent of the patients initial dose. buy viagra jelly
There have been no reported cases of a mebendazole-theophylline interaction. However, we present another well documented case of theophylline toxicity due to the addition of thiabendazole. This prompted us to perform a normal human volunteer study on the effects of steady-state thiabendazole or mebendazole on single-dose theophylline pharmacokinetics.