Editing Ciprofloxacin (section)

== Interactions ==
Ciprofloxacin interacts with certain foods and several other drugs leading to undesirable increases or decreases in the serum levels or distribution of one or both drugs.

Ciprofloxacin should not be taken with antacids containing magnesium or aluminum, highly buffered drugs ([[sevelamer]], [[lanthanum carbonate]], [[sucralfate]], [[didanosine]]), or with supplements containing calcium, iron, or zinc. It should be taken two hours before or six hours after these products. Magnesium or aluminum antacids turn ciprofloxacin into insoluble salts that are not readily absorbed by the intestinal tract, reducing peak serum concentrations by 90% or more, leading to therapeutic failure. Additionally, it should not be taken with dairy products or calcium-fortified juices alone, as peak serum concentration and the area under the serum concentration-time curve can be reduced up to 40%. However, ciprofloxacin may be taken with dairy products or calcium-fortified juices as part of a meal.<ref name="FDA 81532304, R.1"/><ref>{{cite journal |vauthors = Rodvold KA, Piscitelli SC |title = New oral macrolide and fluoroquinolone antibiotics: an overview of pharmacokinetics, interactions, and safety |journal = Clinical Infectious Diseases |volume = 17 |pages = S192–9 |date = August 1993 |issue = Suppl 1 |pmid = 8399914 |doi = 10.1093/clinids/17.supplement_1.s192 }}</ref><ref name="Bolhuis MS, Panday PN, Pranger AD, Kosterink JG, Alffenaar JW 2011 865–913">{{cite journal |vauthors = Bolhuis MS, Panday PN, Pranger AD, Kosterink JG, Alffenaar JW |title = Pharmacokinetic drug interactions of antimicrobial drugs: a systematic review on oxazolidinones, rifamycines, macrolides, fluoroquinolones, and Beta-lactams |journal = Pharmaceutics |volume = 3 |issue = 4 |pages = 865–913 |date = November 2011 |pmid = 24309312 |pmc = 3857062 |doi = 10.3390/pharmaceutics3040865 |doi-access = free | title-link = doi }}</ref>

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.<ref name="Bolhuis MS, Panday PN, Pranger AD, Kosterink JG, Alffenaar JW 2011 865–913"/><ref name="Cipro FDA label" /><ref>{{cite journal |vauthors = Janknegt R |title = Drug interactions with quinolones |journal = The Journal of Antimicrobial Chemotherapy |volume = 26 Suppl D |pages = 7–29 |date = November 1990 |pmid = 2286594 |doi = 10.1093/jac/26.suppl_D.7 }}</ref>

The [[Committee on Safety of Medicines]] and the FDA warn that [[central nervous system]] adverse effects, including seizure risk, may be increased when [[NSAID]]s are combined with quinolones.<ref name="Cipro FDA label" /><ref>{{cite book |title=British National Formulary (BNF 57) |author=Royal Pharmaceutical Society of Great Britain |author-link=Royal Pharmaceutical Society of Great Britain |publisher=BMJ Group and RPS Publishing |chapter=5 Infections |year=2009 |isbn=978-0-85369-845-6 |title-link=British National Formulary }}</ref> The mechanism for this interaction may involve a [[Synergy|synergistic]] increased antagonism of GABA neurotransmission.<ref name="pmid11172695">{{cite journal |vauthors = De Sarro A, De Sarro G |title = Adverse reactions to fluoroquinolones. an overview on mechanistic aspects |journal = Current Medicinal Chemistry |volume = 8 |issue = 4 |pages = 371–84 |date = March 2001 |pmid = 11172695 |doi = 10.2174/0929867013373435 }}</ref><ref>{{cite journal |vauthors = Brouwers JR |title = Drug interactions with quinolone antibacterials |journal = Drug Safety |volume = 7 |issue = 4 |pages = 268–81 |year = 1992 |pmid = 1524699 |doi = 10.2165/00002018-199207040-00003 |s2cid = 6701544 }}</ref>

Altered serum levels of the antiepileptic drugs [[phenytoin]] and [[carbamazepine]] (increased and decreased) have been reported in patients receiving concomitant ciprofloxacin.<ref name="Cipro FDA label" /><ref>{{cite journal |vauthors = Shahzadi A, Javed I, Aslam B, Muhammad F, Asi MR, Ashraf MY |title = Therapeutic effects of ciprofloxacin on the pharmacokinetics of carbamazepine in healthy adult male volunteers |journal = [[Pakistan Journal of Pharmaceutical Sciences]] |volume = 24 |issue = 1 |pages = 63–8 |date = January 2011 |pmid = 21190921 }}</ref><ref>{{cite journal |vauthors = Springuel P |title = Risk of seizures from concomitant use of ciprofloxacin and phenytoin in patients with epilepsy |journal = Canadian Medical Association Journal |volume = 158 |issue = 1 |pages = 104–5, 108–9 |date = January 1998 |pmid = 9475922 }}</ref>

Ciprofloxacin is a potent inhibitor of [[CYP1A2]], [[CYP2D6]], and [[CYP3A4]].<ref name="HaddadDavis2006">{{cite journal |vauthors = Haddad A, Davis M, Lagman R |title = The pharmacological importance of cytochrome CYP3A4 in the palliation of symptoms: review and recommendations for avoiding adverse drug interactions |journal = Supportive Care in Cancer |volume = 15 |issue = 3 |pages = 251–7 |date = March 2007 |pmid = 17139496 |doi = 10.1007/s00520-006-0127-5 |s2cid = 9186457 }}</ref>