<prompt> Ciprofloxacin should not be used with theophylline because-it decreases efficiency of theophyllineit increases toxicity of theophyllineit decreases efficiency of ciprofloxacinit decreases absorption of theophylline  <response>: Ans. is b i.e., It increases the toxicity of theophylline Impoant interactions of FOs o Plasma concentration of theophylline, caffine and warfarin are increased by ciprofloxacin, norfloxacin and pefloxacin. o NSAIDSs enhance CNS toxicity of FQS. o Antacids, sucralfate and iron salts reduce absorption of FQs. 