Clarithromycin

Clarithromycin

[1 vial $30]

ADMINISTRATION ROUTES:

• IV, PO

ALTERNATIVE NAMES:

• Klacid, Klamycin, Clarac

ICU INDICATIONS:

1. treatment of infections caused by susceptible organisms

PRESENTATION AND ADMINISTRATION:

• PO:
  Clarac 250mg tablets (yellow), Klacid 250mg tablets (yellow), Klamycin 250mg tablets (yellow), Klacid suspension 125mg/5ml
• IV:
  For initial reconstitution add 10ml of Water for Injection ONLY to a 500mg vial. Dilute the reconstituted solution (500mg/10ml) in at least 250ml of compatible IV fluid. Infuse over 60 minutes. The initial reconstituted solution is stable for 24 hours when stored at room temperature or refrigerated. The final diluted solution should be used within 6 hours when stored at room temperature or with 24 hours if refrigerated. Compatible with the following IV fluids:
  Normal saline, 5% dextrose, glucose and sodium chloride, Hartmanns
  Do not mix with other medications or IV fluids

DOSAGE:

• PO:
  250mg-500mg 12hrly
• IV:
  500mg 12hrly

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

• Dose in renal impairment [GFR (ml/min)]
  <10: Oral: 250mg every 12 hours; IV: 250mg every 12 hours
  10-20: Oral: 250mg every 12 hours; IV: 250-500mg every 12 hours
  >20-50: dose as in normal function
• Dose in renal replacement therapy
  CAPD: Oral: 250mg every 12-24 hours; IV: 250mg every 12 hours
  HD: Oral: 250mg every 12-24 hours; IV: 250mg every 12 hours
  CVVHDF: Oral: 250mg every 12 hours; IV: 250-500mg every 12 hours

DOSAGE IN PAEDIATRICS:

• PO/IV:
  7.5-15mg/kg 12 hourly

CLINICAL PHARMACOLOGY:

• Clarithromycin is a semi-synthetic macrolide antibiotic. Clarithromycin exerts its antibacterial action by binding to the 50S ribosomal subunit of susceptible microorganisms resulting in inhibition of protein synthesis.
• Clarithromycin has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections:
• Aerobic Gram-Positive Microorganisms:
  Staphylococcus aureus
  Streptococcus pneumoniae
  Streptococcus pyogenes
• Aerobic Gram-Negative Microorganisms:
  Haemophilus influenzae
  Haemophilus parainfluenzae
  Moraxella catarrhalis
• Other Microorganisms:
  Mycoplasma pneumoniae
  Chlamydia pneumoniae (TWAR)
  Mycobacterium avium complex (MAC) consisting of: Mycobacterium avium, Mycobacterium intracellulare

CONTRAINDICATIONS:

1. hypersensitivity to clarithromycin

WARNINGS

• Pseudomembranous colitis
  Pseudomembranous colitis has been reported with nearly all antibacterial agents, including clarithromycin, and may range in severity from mild to life threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhoea subsequent to the administration of antibacterial agents.

PRECAUTIONS

• General:
  Prescribing clarithromycin in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
• Laboratory Tests:
  No tests in addition to routine ICU tests are required
• Drug/Laboratory Test Interactions:
  None of note

IMPORTANT DRUG INTERACTIONS FOR THE ICU

• Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations. Monitoring of serum theophylline concentrations should be considered for patients receiving high doses of theophylline or with baseline concentrations in the upper therapeutic range.
• Spontaneous reports in the postmarketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of warfarin.
• Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have also been reported in postmarketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Serum digoxin concentrations should be carefully monitored while patients are receiving digoxin and clarithromycin simultaneously.
• There have been postmarketing reports of colchicine toxicity with concomitant use of clarithromycin and colchicine, especially in the elderly, some of which occurred in patients with renal insufficiency.
• As with other macrolides, clarithromycin has been reported to increase concentrations of HMG-CoA reductase inhibitors (e.g., lovastatin and simvastatin). Rare reports of rhabdomyolysis have been reported in patients taking these drugs concomitantly. Erythromycin has been reported to increase the systemic exposure (AUC) of sildenafil. A similar interaction may occur with clarithromycin; reduction of sildenafil dosage should be considered.

ADVERSE REACTIONS

• Body as a whole:
  Anaphylaxis
• Gastrointestinal system:
  Diarrhoea, nausea, abnormal taste, dyspepsia, abdominal pain/discomfort, cholestasis, hepatitis
• Haematological system:
  Thrombocytopenia, leukopenia, neutropenia