Concurrent administration of ciprofloxacin and theophylline can cause an undesirable increase in the serum theophylline concentration. This can lead to theophylline-induced side effects; in very rare cases, these side effects can be life-threatening or fatal. If concurrent use of the 2 products is unavoidable, the serum theophylline concentration should therefore be checked and the theophylline dose appropriately reduced.
Animal studies have shown that the combination of very high doses of quinolones (gyrase inhibitors) and certain nonsteroidal anti-inflammatory agents (but not acetylsalicylic acid) can provoke convulsions.
A transient rise in the concentration of serum creatinine was observed when ciprofloxacin and cyclosporin were administered simultaneously.
Therefore, it is necessary to control the serum creatinine concentrations in these patients frequently (twice a week).
The simultaneous administration of ciprofloxacin and warfarin may intensify the action of warfarin.
In particular cases, concurrent administration of ciprofloxacin and glibenclamide can intensify the action of glibenclamide (hypoglycaemia). Probenecid interferes with renal secretion of ciprofloxacin. Co-administration of probenecid and ciprofloxacin increases the ciprofloxacin serum concentrations.
Renal tubular transport of methotrexate may be inhibited by concomitant administration of ciprofloxacin, potentially leading to increased plasma levels of methotrexate and increased risk of methotrexate associated toxic reactions.
Therefore, patients under methotrexate therapy should be carefully monitored when concomitant ciprofloxacin therapy is indicated.
The simultaneous administration of ciprofloxacin and iron, sucralfate or antacids and highly buffered drugs (eg, didanosine tablets), containing magnesium, aluminium, or calcium reduce the absorption of ciprofloxacin. Consequently, ciprofloxacin should be administered either 1-2 hrs before, or at least 4 hrs after these preparations. This restriction does not apply to antacids belonging to the class of H2-receptor blockers.
Metoclopramide accelerates the absorption of ciprofloxacin resulting in a shorter time to reach maximum plasma concentrations. No effect was seen on the bioavailability of ciprofloxacin.