However, ciprofloxacin may be taken with dairy products or calcium-fortified juices as part of a meal.Ciprofloxacin inhibits the drug-metabolizing enzyme CYP1A2 and thereby can reduce the clearance of drugs metabolized by that enzyme. CYP1A2 substrates that exhibit increased serum levels in ciprofloxacin-treated patients include tizanidine, theophylline, caffeine, methylxanthines, clozapine, olanzapine, and ropinirole. Co-administration of ciprofloxacin with the CYP1A2 substrate tizanidine (Zanaflex) is contraindicated due to a 583% increase in the peak serum concentrations of tizanidine when administered with ciprofloxacin as compared to administration of tizanidine alone. Use of ciprofloxacin is cautioned in patients on theophylline due to its narrow therapeutic index. The authors of one review recommended that patients being treated with ciprofloxacin reduce their caffeine intake. Evidence for significant interactions with several other CYP1A2 substrates such as cyclosporine is equivocal or conflicting.The Committee on Safety of Medicines and the FDA warn that central nervous system adverse effects, including seizure risk, may be increased when NSAIDs are combined with quinolones. The mechanism for this interaction may involve a synergistic increased antagonism of GABA neurotransmission.Altered serum levels of the antiepileptic drugs phenytoin and carbamazepine (increased and decreased) have been reported in patients receiving concomitant ciprofloxacin.Ciprofloxacin is a potent inhibitor of CYP1A2, CYP2D6, and CYP3A4. Mechanism of action
Ciprofloxacin is a broad-spectrum antibiotic of the fluoroquinolone class. It is active against some Gram-positive and many Gram-negative bacteria. It functions by inhibiting a type II topoisomerase (DNA gyrase) and topoisomerase IV, necessary to separate bacterial DNA, thereby inhibiting cell division.
Cancer
Ciprofloxacin is active in six of eight in vitro assays used as rapid screens for the detection of genotoxic effects, but is not active in in vivo assays of genotoxicity. Long-term carcinogenicity studies in rats and mice resulted in no carcinogenic or tumorigenic effects due to ciprofloxacin at daily oral dose levels up to 250 and 750 mg/kg to rats and mice, respectively (about 1.7 and 2.5 times the highest recommended therapeutic dose based upon mg/m2). Results from photo co-carcinogenicity testing indicate ciprofloxacin does not reduce the time to appearance of UV-induced skin tumors as compared to vehicle control. Other
The other black box warning is that ciprofloxacin should not be used in people with myasthenia gravis due to possible exacerbation of muscle weakness which may lead to breathing problems resulting in death or ventilator support. Fluoroquinolones are known to block neuromuscular transmission. There are concerns that fluoroquinolones including ciprofloxacin can affect cartilage in young children.Clostridium difficile-associated diarrhea is a serious adverse effect of ciprofloxacin and other fluoroquinolones; it is unclear whether the risk is higher than with other broad-spectrum antibiotics.A wide range of rare but potentially fatal adverse effects reported to the U.S. FDA or the subject of case reports includes aortic dissection, toxic epidermal necrolysis, Stevens–Johnson syndrome, low blood pressure, allergic pneumonitis, bone marrow suppression, hepatitis or liver failure, and sensitivity to light. The medication should be discontinued if a rash, jaundice, or other sign of hypersensitivity occurs.Children and the elderly are at a much greater risk of experiencing adverse reactions.