Urgent help neededif 92 yo patient wont take large 500mg kelfex capsule bid after rocephin for klebsiella uti, can i substitute 250mg cipro (ciprofloxacin) tablet bid?

No. Call the doctor.: You can ask them to substitute a liquid version of the same medication, but don't substitute another medication on your own.

See below: You can get Keflex oral suspension. I avoid floroquinolones like Cipro (ciprofloxacin) in the elderly because of a higher risk of side effects such as tendonitis/tendon rupture, CNS toxicities and nap1 clostridium difficile disease.