Ciprofloxacin (500mg Tablet)

Availability

Prescription Drug (Rx)

Therapeutic Class

Belongs to the class of fluoroquinolones. Used in the systemic treatment of infections.

Mode of Action

Description: Ciprofloxacin, a fluoroquinolone anti-infective agent, acts by inhibiting DNA gyrase and topoisomerase IV, both essential in bacterial DNA replication, transcription, repair and recombination.

Pharmacokinetics:

Absorption: Rapid and well absorbed from the gastrointestinal tract. Bioavailability: Approx 70-80% . Time to peak plasma concentration: 0.5-2 hours (conventional tab); 1-2.5 hours (extended-release tab).

Distribution: Widely distributed in the tissues. Crosses placenta, enters breast milk, bile (high concentrations), and CSF (10% noninflamed meninges; 14-37% inflamed meninges). Volume of distribution: 2.1-2.7 L/kg. Plasma protein binding: 20-40%.

Metabolism: Partially metabolised in the liver to desthyleneciprofloxacin (M1), sulphociprofloxacin (M2), oxociprofloxacin (M3), and formylciprofloxacin (M4) in low concentrations.

Excretion: Via urine [approx 40-50% as unchanged drug, approx 15%, as metabolites (oral); 70% as unchanged drug, 10% as metabolites (parenteral)]; faeces [20-35% (oral), 15% (IV)]. Elimination half-life: Approx 3-5 hours.

Indication

Treatment of resp tract infections, UTI, chronic prostatitis, gonorrhea. Meningococcal meningitis & surgical infection prophylaxis.

Dosage

Adult 250-750 mg bid. Gonorrhea 250 or 500 mg as a single dose. Meningococcal meningitis prophylaxis 500 mg as a single dose. Surgical infection prophylaxis 750 mg as a single dose administered 60-90 min pre-op.

Contraidication

Hypersensitivity to ciprofloxacin or other quinolones. Concomitant use with tizanidine. History or risk of QT prolongation.

Special Precaution

Epilepsy or a history of CNS disorders. Avoid MRSA infections.

Drug Interaction

Increased risk of prolonged QT interval with Class IA (e.g. quinidine, procainamide) and Class III (e.g. amiodarone, sotalol) antiarrhythmics, TCA, macrolides (e.g. erythromycin), cisapride, antipsychotics. Increased serum concentration with probenecid. May increase serum concentration and toxicity of methotrexate; CYP1A2 substrates (e.g. clozapine, ropinirole, theophylline); xanthine derivatives (e.g. caffeine, pentoxifylline). Increased risk of tendon disorders with corticosteroids. Increased serum creatinine with cyclosporin. Increased risk of convulsions with NSAIDs. May alter serum concentrations of phenytoin. Reduced oral absorption with products containing multivalent cations (e.g. Al, Ca, Mg, Fe). May increase anticoagulant effect of vit K, warfarin.
Potentially Fatal: May increase serum concentration and potentiate hypotensive and sedative effects of tizanidine. Rarely, serious and fatal seizures, status epilepticus, cardiac arrest, respiratory failure with theophylline.