What is clarithromycin, and how does it work (mechanism of action)?
Clarithromycin is a semi-synthetic macrolide antibiotic chemically related to erythromycin and azithromycin (Zithromax).
It is effective against a wide variety of bacteria, such as Haemophilus
influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Staphylococcus
aureus, and mycobacterium avium, and many others. Like all macrolide
antibiotics, clarithromycin prevents bacteria from growing by interfering with
their ability to make proteins. Due to the differences in the way proteins are
made in bacteria and humans, the macrolide antibiotics do not interfere with
production of proteins in humans. The FDA approved clarithromycin in October
What brand names are available for clarithromycin?
Is clarithromycin available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for clarithromycin?
What are the uses for clarithromycin?
Clarithromycin is effective against susceptible bacteria causing
the following infections:
- middle ear,
- throat infections,
- pneumonia, and
- skin infections.
It also is used in
treating infections caused by mycobacterium avium, a bacterium closely related
to the bacterium that causes tuberculosis. Clarithromycin has been used in
combination with omeprazole/sodium bicarbonate (Prilosec) in
treating H. Pylori that causes stomach ulcers.
Bowel regularity means a bowel movement every day.
What are the side effects of clarithromycin?
Clarithromycin generally is well tolerated, and side
effects usually are mild and transient. Common side effects of clarithromycin are:
- abnormal taste,
- abdominal pain and
Other important side effects which are rare, but serious include:
- liver failure,
- abnormal heart beats,
- hearing loss, and
Clarithromycin should be avoided by patients known
to be allergic to clarithromycin or other chemically-related macrolide
antibiotics, such as erythromycin. Treatment with clarithromycin and other
antibiotics can alter the normal bacteria flora of the colon and permit
overgrowth of C. difficile, a bacterium responsible for
pseudomembranous colitis. Patients who develop pseudomembranous colitis as a result of
antibiotics treatment may experience diarrhea, abdominal pain, fever, and
sometimes even shock.
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What is the dosage for clarithromycin?
Clarithromycin may be taken with or without food. For most
infections the recommended adult dose is 250-500 mg of immediate release tablets
twice daily or 1000 mg of extended release tablets once daily for 7-14 days.
Which drugs or supplements interact with clarithromycin?
Clarithromycin interacts with several drugs because
it reduces the activity of liver enzymes that breakdown many drugs. This leads
to increased blood levels and side effects from the affected drugs. Examples of
such interactions include
- simvastatin (Zocor),
- lovastatin (Mevacor),
- atorvastatin (Lipitor),
- verapamil (Calan),
- amlodipine (Norvasc), and
- diltiazem (Carizem).
increases blood levels of sildenafil (Viagra, Revatio), tadalafil (Cialis,
vardenafil (Levitra), theophylline and
increasing side effects of these drugs.
Ritonavir (Norvir) and atazanavir (Reyataz)
increase blood levels of clarithromycin while efavirenz (Sustiva), nevirapine (Viramune),
rifampin, decrease blood levels of clarithromycin.
Itraconazole (Sporanox) and
saquinavir (Invirase) may increase blood levels of clarithromycin while
clarithromycin increases blood levels or both drugs.
The occurrence of abnormal
heart beats may increase when clarithromycin is combined with drugs that affect
heart beat (for example, amiodarone
[Quinidine Gluconate, Quinidine Sulfate], and disopyramide).
Is clarithromycin safe to take if I’m pregnant or breastfeeding?
Safe use of clarithromycin in
pregnancy has not been
established. There are no adequate studies in pregnant women.
Clarithromycin is excreted in breast milk.
What else should I know about clarithromycin?
What preparations of clarithromycin are available?
Tablets (immediate or extended release): 250 and 500 mg.
Suspension: 125 or 250 mg per 5 ml (teaspoonful).
How should I keep clarithromycin stored?
Tablets and suspension should be stored at room temperature
15 -30 C (59-86 F) in a tightly closed container. The oral suspension should not
be refrigerated after mixing and should be used within 14 days.