What are the recommendations for using ciprofloxacin (Cipro) in a patient with a bacterial infection, considering factors such as renal function, history of tendonitis, and potential interactions with other medications?

Ciprofloxacin Recommendations

Ciprofloxacin is a broad-spectrum fluoroquinolone that should be reserved for specific infections where other agents cannot be used, with critical attention to renal dosing, tendon rupture risk (especially in patients >60 years, on corticosteroids, or with transplants), and drug interactions. 1

FDA Black Box Warning

• All patients must be counseled about the increased risk of tendinitis and tendon rupture, which is further elevated in patients >60 years, those taking corticosteroids, and kidney/heart/lung transplant recipients. 1
• Patients should immediately discontinue ciprofloxacin and contact their provider if they experience tendon pain, swelling, inflammation, or joint weakness. 1
• The risk of Achilles tendinitis can develop within days of starting treatment, even at reduced doses in elderly patients with renal dysfunction. 2

Dosing by Indication

Uncomplicated Cystitis

• Ciprofloxacin 250 mg orally twice daily for 3 days is highly effective but should be reserved as an alternative when other agents (nitrofurantoin, trimethoprim-sulfamethoxazole, fosfomycin) cannot be used. 3, 4
• This restriction is due to concerns about antimicrobial resistance and collateral damage to normal flora. 5, 4

Acute Pyelonephritis

• Use ciprofloxacin 500 mg orally twice daily for 7 days ONLY when local fluoroquinolone resistance is ≤10%. 5, 3, 4
• Alternative: Ciprofloxacin 1000 mg extended-release once daily for 7 days. 4
• If local resistance exceeds 10%, give an initial one-time IV dose of ceftriaxone 1g or a consolidated 24-hour aminoglycoside dose before starting oral ciprofloxacin. 5, 4
• Optional initial IV dose: 400 mg ciprofloxacin before transitioning to oral therapy. 5, 4
• Always obtain urine culture and susceptibility testing before initiating therapy. 5, 4

Complicated UTI/Pseudomonas Infections

• Standard dosing: 500 mg orally twice daily for 7 days. 4
• If local fluoroquinolone resistance exceeds 10%, consider initial parenteral therapy before switching to oral. 4

Other Infections

• Diabetic wound infections (moderate to severe): Ciprofloxacin combined with clindamycin for anaerobic coverage. 6
• Surgical site infections (axilla/perineum): Ciprofloxacin or levofloxacin combined with metronidazole. 6
• Spontaneous bacterial peritonitis prophylaxis: Ciprofloxacin 500 mg/day for 12 months in cirrhotic patients with ascitic fluid protein <15 g/L and moderate liver failure improved 1-year survival (86% vs 66%). 6

Renal Dosing Adjustments

• For creatinine clearance <30 mL/min: Give oral loading dose of 500 mg, then 250 mg every 24 hours. 3
• Major dosage adjustments are not required until creatinine clearance is <30 mL/min or serum creatinine ≥2 mg/dL. 7
• In renal failure, prolonging the administration interval (500 mg every 24 hours) is superior to dose reduction (250 mg every 12 hours) for bacterial eradication. 8

Critical Drug Interactions

Absolute Contraindication

• Never use ciprofloxacin with tizanidine (Zanaflex)—ciprofloxacin increases tizanidine effects significantly. 1

Significant Interactions Requiring Separation

• Antacids, calcium, iron, zinc, magnesium: Take ciprofloxacin at least 1-2 hours before or 4-6 hours after these products. 6, 1
• Dairy products or calcium-fortified juices alone: Avoid concurrent administration as absorption is significantly reduced; however, ciprofloxacin may be taken with a meal containing these products. 1
• Theophylline: Ciprofloxacin increases theophylline levels—reduce theophylline dose and monitor levels closely. 6, 1

Monitor Closely

• Warfarin and other anticoagulants: Monitor INR. 6
• Drugs prolonging QT interval (class IA/III antiarrhythmics, tricyclic antidepressants, macrolides, antipsychotics): Use with caution. 6
• Methotrexate: Increased toxicity risk. 6
• Cyclosporine: Increased nephropathy risk. 6

Special Precautions

Hydration and Crystalluria

• Patients must be well hydrated to prevent crystalluria, which occurs more frequently in alkaline urine. 1
• Avoid alkalinity of urine in patients receiving ciprofloxacin. 1

Photosensitivity

• Moderate to severe photosensitivity reactions can occur—patients should minimize sun/UV exposure and wear protective clothing. 1
• Discontinue immediately if sunburn-like reaction or skin eruption occurs. 1

Central Nervous System Effects

• Ciprofloxacin may cause nervousness, agitation, insomnia, anxiety, nightmares, paranoia, dizziness, and lightheadedness. 1
• Convulsions have been reported—use with caution in patients with seizure history. 1
• Patients should not operate vehicles or machinery until they know how they react to the drug. 1

Peripheral Neuropathy

• If symptoms of peripheral neuropathy (pain, burning, tingling, numbness, weakness) develop, discontinue treatment immediately and contact physician. 1

Pediatric Use

• Ciprofloxacin is associated with increased rate of adverse events involving joints and surrounding tissues in patients <18 years. 1
• Pediatric dosing: 20-40 mg/kg/day divided every 12 hours, maximum 750 mg per dose. 3
• Consider pediatric infectious diseases consultation before use in children. 4

Administration Guidelines

• May be taken with or without meals. 1
• Drink fluids liberally during treatment. 1
• Complete the full course even if feeling better early—skipping doses increases resistance risk. 1
• Sequential IV to oral therapy offers cost savings and may allow early hospital discharge in appropriate patients. 7

Common Pitfalls to Avoid

1. Do not use ciprofloxacin as first-line empirical therapy for respiratory tract infections if penicillin-susceptible Streptococcus pneumoniae is the primary pathogen. 7
2. Do not prescribe without considering local resistance patterns—efficacy drops significantly when the uropathogen is resistant to fluoroquinolones. 5
3. Do not forget to adjust dosing in elderly patients with renal dysfunction—even standard doses can cause tendinitis within days. 2
4. Do not continue quinolone prophylaxis in patients who develop quinolone-resistant bacterial infections. 6