Ciprofloxacin HCl (Cipro)

  • Generic name: Ciprofloxacin hydrochloride
  • Brand names: Cipro, Ciprobay, Ciloxan, Proquin, Baycip
  • Drug class: Fluoroquinolone antibiotic

What is Ciprofloxacin used for?

  • Urinary tract infections - cystitis, pyelonephritis. Ciprofloxacin is active against most pathogenic bacteria in the urinary tract and is a good option when other antibiotics fail to cure UTI.
  • Chronic bacterial prostatitis
  • Skin and bone infections
  • Inhalational anthrax
  • Infectious diarrhea, Shigellosis
  • Some sexually transmitted diseases.

Ciprofloxacin is NOT recommended for:

  • Pneumonia: Ciprofloxacin should not be used to treat pneumonia because of its poor activity against S. pneumoniae.
  • Chlamydia: Ciprofloxacin has inadequate activity against C. trachomatis.
  • Gonorrhoea: Ciprofloxacin is no longer recommended as first-line treatment for gonorrhoea because of increased resistance of N. gonorrhoeae3.

Strict contraindications

  • Known hypersensitivity to ciprofloxacin or any fluoroquinolone.
  • Concomitant use with tizanidine.

Ciprofloxacin and tendon damage

Tendinitis and tendon rupture are now well recognised but rare serious side effect of ciprofloxacin and other fluoroquinolones.

Most of the tendinitis and tendon ruptures affect the Achilles tendon, followed by quadriceps femoris tendon, rotator cuff tendons (especially supraspinatus) and biceps brachii tendon, although any tendon can be affected.

These risk factors include age over 60 years, use of corticosteroids, and renal failure. People aged >60 years have been found to have a threefold increased relative risk of tendon damage, whereas concurrent corticosteroid use in this elderly group has been found to have a sixfold increased risk1.

Serious drug interactions

  • Antacids (aluminum- and magnesium-containing), calcium, iron salts, zinc salts - decreased oral absorption of fluoroquinolones.
  • Clozapine - increased clozapine concentrations.
  • Glyburide - severe hypoglycemia reported.
  • Phenytoin - altered phenytoin concentrations.
  • Theophylline derivatives - increased theophylline concentrations, which may result in toxicity and death. Interaction between ciprofloxacin and theophylline can be clinically significant.
  • Tizanidine - levels of tizanidine may be elevated 7-fold. Concomitant use contraindicated.

Food interactions

Ciprofloxacin and Milk

Do not take Ciprofloxacin hcl with dairy products such as milk or yogurt2. Calcium in dairy products and other calcium-rich foods can bind to ciprofloxacin in the digestive tract, preventing it from being absorbed into the bloodstream.

It is best to take ciprofloxacin at least 2 hours before or 6 hours after drinking milk or eating calcium-rich foods, unless you are eating these foods as part of a meal containing other foods. These other foods will decrease the calcium binding effect.

Ciprofloxacin and Caffeine

Limit consumption of coffee, tea, or caffeine-containing drinks. Regular consumption of large quantities of caffeine-containing products during treatment with ciprofloxacin may cause caffeine to accumulate in the body, resulting in exaggerated caffeine effects.


  • 1. Van der Linden P, Sturkenboom M C, Herings R M. et al Fluoroquinolones and risk of Achilles tendon disorders: case‐control study. BMJ 2002. 3241306–1307.1307.
  • 2. Neuvonen PJ, Kivistö KT, Lehto P. Interference of dairy products with the absorption of ciprofloxacin. Clin Pharmacol Ther. 1991 Nov;50(5 Pt 1):498-502.
  • 3. CDC Changes Recommendations for Gonorrhea

Author: OriginalDrugs Team
Last reviewed: February, 2015

Good to know

ciprobay 500 mg
  • The discovery and development of ciprofloxacin is that rare case of an actual groundbreaking new drug development, opening up an entire new class of antibiotics for further research, development, and marketing.
  • It is a rare case where the first drug discovered of this class remains the 'gold standard' in terms of efficacy, with the other drugs developed by other pharmaceutical companies relegated to 'me-too' status and forced to compete on the basis of lower cost.
  • Ciprofloxacin is the fluoroquinolone most studied in children, mostly when used to treat pulmonary exacerbations of CF.