Drug interactions- summary

 Clarithromycin +

 Anticoagulants

incr effects of anticoagulants potentiated,monitor PT Antihitamines incr following coadministration, plasma levels of the active metabolite of terfenadine were threefold higher on average. Do not use concurrently in patients who have preexisting cardiac abnormalities or electrolyte disturbances

Carbamazepine

 increased concentrations of carbamazepine occur Consider monitoring carbamazepine levels

Cisapride

 serious cardiac arrhythmias(some fatal) including ventricular tachycardia, ventricular fibrillation, torsade de pointes and QT prolongation have been reported in patients taking cisapride with other drugs that inhibit cytochrome P 450 IIIA4. Concurrent use is contraindicated

Cyclosporine

 elevated cyclosporine with increased risk of toxicity (nephrotoxicity, neurotoxicity) occur

Digoxin

serum digoxin levels elevated

Ergot alkaloids

 acute ergot toxicity characterised by severe peripheral vasospasm and dyesthesia has occured

Fluconazole + Clarithromycin

 concomittant fluconazole led to increase in mean steady state clarithromycin

Clarithromycin + Tacrolimus

plasma tracolimus levels may be increased incresing the risk of toxicity

Clarithromycin + Theophyllines 

concurrent use associated with increased serum theophylline.Consider monitoring theophylline levels

Clarithromycin +Triazolam

 CNS effects(eg. somnolence, confusion) have occurred

Clarithromycin +Zidovudine

 simultaneous use in HIV- infested patients resulted in decreased steady-state zidovudine levels. Peak serum zidovudine conc. increased or decreased

Diarrhoea,nausea,dyspepsia,abdominal pain/discomfort,headache.

Hypersensensitivity to Clarithromycin,erythromycin or anyof the macrolide antibiotics.

Special precautions:

Pseudomembranous colitis has occurred with nearly all antibacterial agents and may range in severity to mild to life threatening.

It is important to consider this diagnosis in patients who present with diarrhoea susequent to administration of antibacterial agents.

Hepatic/renal function impairment, elderly, pregnancy.

Clarithromycin was approved by the FDA in October 1991.

Pharyngitis/  Tonsilitis

Dosage:

Adults- 500mg twice daily

Children- 7.5mg/kg twice daily up to 500mg twice daily.

Clarithromycin may be given without regard to meals and can be taken with milk

. 1. Allergies- Tell your doctor if you have ever had any unusual or allergic raections to clarithromycin or other related medicines. Also tell your doctor if younare allergic to to any other substances suchas foods, precervatives or dyes.

2. Pregnancy- make sure your doctor knows if you are pregnant or if you become pregnant.

3. Breast feeding- clarithromycin passes intop breast milk.

4. Children- this medicine has not beenshown to cause different side effects or problems in children over the age of 6 months than it does in adults.

5. Elderly- elderly patients has not ben shown to cause different side effects or problems tthan in younger adults.

6. Other medicines- tell your doctor if you are taking any other medicines- Carbamazepine or Digitoxin or Terfenadine or Theophylline or Warfarin - clarithromycin may increase the chance of side effects of these medicines.

7. Other medical problems- tell your doctor if you have any other medical problems- Kidney disease- patients with severe kidney disease may have an increased chance of side effects.

8. Missed dose- If you miss a dosew of this medicine take it as soon as possible. However if it is almost time for your next dose go back to your regular dosing schedule. Do not double doses.

Clarithromycin can administered without regards for meals

Pregnancy:

Has adverse effects on pregnancy. Do not use Clarithromycin in pregnant women.

Lactation:

Excreted in breast milk. Excercise caution when administering to a nursing woman

Children:

Safety and efficacy in children less than 6 months have not been established