Ranitidine Levothyroxine

Noninterfering acetaminophen, N-acetylprocainamide, amikacin, amitriptyline, amlodi-pine, carbamazepine, cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, cisapride, clindamycin, clonidine, codeine, cyclosporine, digoxin, diphenhydramine, disopyramide, ethosuximide, fluconazole, gentamicin, gentamicin, heparin, labetalol, levothyroxine, li-docaine, lithium, methotrexate, metronidazole, minoxidil, nafcillin, nifedipine, phenobar-bital, phenobarbital, phenytoin, phenytoin, primidone, procainamide, propranolol, quini-dine, ranitidine, salicylic acid, theophylline, tobramycin, tobramycin, valproic acid, warfarin... 

Cimetidine, but not ranitidine, causes a small reduction in the absorption of levothyroxine. 

When 10 women with simple goitre were given 400 mg of cimetidine 90 minutes before a single capsule of levothyroxine, the absorption of levothyroxine was reduced over the first 4 hours by about 21%. The reasons are not understood. A single 300-mg dose of ranitidine was found not to affect the levothyroxine absorption in a matched group of 10 women. ... 

Jonderico G, Jonderico K, Marcisz CZ, Kotulska A. Effect of cimetidine and ranitidine on absorption of [ I] levothyroxine administered ccally.y4c/aP amiaco/5iH (1992) 13,391. ... 

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