Ranitidine and theophylline.
D000368:Aged; D000863:Antacids / Q000009:adverse effects*; D004347:Drug Interactions; D006801:Humans; D011899:Ranitidine / Q000009:adverse effects*; D013806:Theophylline / Q000378:metabolism*
D000863:Antacids; D011899:Ranitidine; D013806:Theophylline