Ciprofloxacin interaction with other drugs

This appears to be an isolated case but it is consistent with the way rifampicin interacts with other drugs. Clozapine serum levels should be well monitored if rifampicin is added, being alert for the need to increase its dosage. An alternative (as in this case) is to use another antibacterial. However, note that there are reports of an interaction between clozapine and ciprofloxacin , (p.749). 

All quinolones interact with multivalent cations, forming chelation complexes resulting in reduced absorption. Major offenders are antacids vitamins containing calcium and iron can also be problematic. All fluoroquinolones interact with warfarin, didanosine (ddi), and phenytoin, resulting in decreased absorption or metabolism. Ciprofloxacin and other second-generation drugs interact with theophylline by decreasing its clearance, which leads to theophylline toxicity. 

There are drug products whose interaction with PVC bags and infusion sets are so high that they must include labehng precautions for use with PVC containers. These drugs include antineoplastics such as pachtaxel, docetaxel, tacrolimus, and teniposide, and others such as ciprofloxacin, cefoperazone sodium, fluconazole, metronidazole HC1, cimetidine, and propofol [64,65]. 

Polk RE. Drug-drug interactions with ciprofloxacin and other fluoroquinolones. Am J Med 1989 87(suppl 5A) 76S-81S. 

Information about the interactions with calcium carbonate is more limited than with the aluminium/magnesium antacids, but Table 10.3 , (p.329) shows that the bioavailabilities of ciprofloxacin and norfloxacin, and to a lesser extent gemifloxacin, can be reduced. These reductions are less than those seen with the aluminium/magnesium antacids, but using ciprofloxacin as a guide a very broad rule-of-thumb would be to separate the drug administration by about 2 hours to minimise this interaction. This is clearly not necessary with levofloxacin, lomefloxacin, moxifloxacin or ofloxacin, nor probably with some of the other qui-... 

Probenecid increases the serum ieveis and/or decreases the urinary excretion of cinoxacin, ciprofloxacin, clinafloxacin, enoxacin, fleroxacin, levofloxacin, nalidixic acid and norfloxacin. The ciinicai importance of these changes is uncertain, but is seems iikeiy they wiii oniy be important in the presence of other drugs that aiso affect renai excretion. Grepafloxacin, moxifloxacin, sparfloxacin, and probably ofloxacin, appear not to interact with probenecid. 

Absorption of antimicrobial agents such as fluoroquinolones and tetracyclines that can be bound by divalent and trivalent cations potentially could be compromised by administration with EN formulas containing these cations. The fluoroquinolones (e.g., levofloxacin and ciprofloxacin) have been best studied in this regard, and results of studies are not consistent. Mechanisms for an interaction between fluoroquinolones and EN formulas other than chelation by cations have been postulated.40 Some institutions hold tube feedings for 30 to 60 minutes or more before and after enteral dosages of fluoroquinolones. Because ciprofloxacin absorption has been shown to be decreased with jejunal administration, this drug probably should not be given by jejunal tube.41... 

A number of cases of convulsions have been seen in Japanese patients given fenbufen with enoxacin, and there is also one possible case involving ofloxacin. Use of these particular drugs together should be avoided. Normally no interaction seems to occur with most quinolones and NSAIDs, except where there is a predisposition to convulsive episodes. Isolated cases of convulsions, other neurological toxicity or skin eruptions have been seen when ciprofloxacin was given with indometacin, mefenamic acid or naproxen. These appear to be very rare events. 

Information on this interaction and its clinical relevance is limited. The author of the pharmacokinetic study suggests that, if the drugs need to be used together, the dosage of pentoxifylline should be halved. In the absence of other information, if a short-course of ciprofloxacin is required in a patient taking pentoxifylline, this may be a sensible precaution. Alternatively, because the increase in AUC was minor, it may be sufficient to recommend a reduction in pentoxifylline dose only in those who experience adverse effects (e.g. nausea, headache). Note that ciprofloxacin has been used to boost pentoxifylline levels in studies investigating the possible therapeutic value of pentoxifylline s ability to inhibit various cytokines. For example, ciprofloxacin 500 mg twice daily was used with pentoxifylline 800 mg three times daily for up to one year in patients with myelod-ysplastic syndrome. ... 

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