Inhibitors of p450 cause toxicity of other drugs. The whole class of quinolone antibiotics is associated with case reports of tendon rupture.
- A quinolone antibiotic useful against Pseudomonas
- Inhibitor of p450 (CYP1A2 enzyme) leads to drug interactions
- Well absorbed and distributed and mostly renally excreted
Mode of action
- 4 fluoroquinolones are bactericidal and affect DNA gyrase.
Activity against
- Gram negatives e.g. Salmonella, Pseudomonas, Campylobacter, Neisseria, Haemophilus, E.coli
- Gram positives e.g. Pneumococcus, Enterococcus faecalis
Indication/Dose
- Gram-negative infections. pseudomonas, typhoid, traveller's diarrhoea, gonorrhoea, UTI, anthrax
- Mild infection: Ciprofloxacin 500-750 mg 12 h PO
- Moderate/Severe infection or NBM: Ciprofloxacin 400 mg 12 h IV over 30-60 min
Contraindications
- Pregnancy, Children and adolescents - safety unproven
Cautions
- Avoid orally with aluminium and magnesium antacids
- Epilepsy, Pregnancy, Breastfeeding, Children
- May exacerbate muscle weakness in Myasthenia gravis
Side effects
- GI upset - Nausea, vomiting, diarrhoea
- Insomnia, Confusion, Convulsions, hepatitis
- Lowers seizure threshold
- Tendinitis and tendon rupture (increased if on steroids too)
Interactions (Enzyme inhibitor so increases levels of other drugs)
- Warfarin: Raised INR with Warfarin and potential bleeding
- Theophylline: toxicity so care must be taken or the combination avoided.
- Caffeine: Increased caffeine levels
- Can be bound by antacids reducing absorption and Ciprofloxacin efficacy
- Probenecid interferes with renal tubular secretion of Ciprofloxacin
- Ciclosporin interaction is unproven
References