Clarithromycin

Type of Medication: Antibiotic

Indications: Treatment of community acquired upper and lower respiratory tract infections. Used in low dose in CF and non CF bronchiectasis for anti-inflammatory property. Haemophilus, MSSA, M. abscessus, M. avium infections.

Side Effects: Nausea (less common than erythromycin), vomiting, abdo pain, diarrhoea, urticaria, rashes, reversible hearing loss, cholestatic jaundice. cardiac effects rare i.e chest pain, arrhythmias. local phlebitis with iv, stomatitis, glossitis, headaches, taste alteration, anxiety, dizziness,insomnia, bad dreams, confusion.

Can cause tooth, tongue and urine discolouration

GFR <30mL/min 250‐500mg BD (<10mL/min, vomiting may be a problem with higher doses).

Route of administration: Adult (Intravenous)

Dose:500 mg bd

Administration: Use large proximal vein. Contents of 500 mg vial is dissolved in water and added to 250 ml 5% dextrose or 0.9% saline and given over one hour.

Route of administration: Adult (Oral)

Dose:250 to 500 mg bd

Administration: Available as 250 or 500 mg tablets, 125 mg/ 5ml and 250 mg/5ml suspension and 250 mg sachets. Also available as 500 mr tablets, dose 500 mg daily (doubled in severe infections). Give with food

Route of administration: Paediatric oral

Dose:< 8 kg 7.5 mg/kg bd,1-2 yrs 62.5 mg bd, 3-6 yrs 125 mg bd, 7-9 yrs 187.5 mg bd, 10+ yrs 250 mg bd

Examples of some Drug Interactions

Interacts with some drugs metabolised by CYP450 isoenzyme system – may increase plasma concentrations of drugs such as theophylline, ciclosporin, tacrolimus, simvastatin, warfarin. Contact pharmacist for further advice.

Interacting drug: Carbamazepine – inceased plasma carbamazepine concentration

Interacting drug: Ciclosporin – increases ciclosporin level

Interacting drug: Cisapride – inhibit metabolism of cisapride, and increases risk of arrythmias – avoid

Interacting drug: Digoxin – increases plasma digoxin concentration

Interacting drug: Disopyramide – increased plasma disopyramide concentration

Interacting drug: Itraconazole  – increases plasma itraconazole concentration

Interacting drug: Midazolam – increased plasma midazolam concentration (increased sedation).

Interacting drug: Phenytoin – increases plasma phenytoin concentration

Interacting drug: Pimozide – increased risk of arrythmia- avoid

Interacting drug: Rifabutin – increases plasma rifabutin level(increased risk of uveitis- reduce rifabutin dose).

Interacting drug: Tacrolimus – increases tacrolimus level

Interacting drug: Terfenadine – increases risk of arrythmias – avoid

Interacting drug: Theophylline – increases theophylline level

Interacting drug: Warfarin – increase INR

Interacting drug: Zafirlukast – reduced plasma concentrations of Zafirlukast