How clarithromycin works
Clarithromycin penetrates the bacterial cells and prevents them from producing vital proteins. The bacteria are therefore not killed by the antibiotic, but their growth is inhibited. The active ingredient has a bacteriostatic effect.
This inhibition of bacterial growth gives the immune system the opportunity to contain the infection. Compared to erythromycin, another well-known macrolide antibiotic, clarithromycin is effective against even more types of bacteria.
In addition, unlike erythromycin, it is gastric acid stable, so it does not break down in the stomach. This makes it possible to reduce the frequency with which it is taken. In addition, clarithromycin is more tissue mobile, so it reaches its target in the body much better.
Absorption, degradation and excretion
About six hours after ingestion, half of the active substance is excreted again, about three-quarters in the stool and one-quarter in the urine.
When is clarithromycin used?
Clarithromycin is used to treat bacterial infections caused by clarithromycin-susceptible pathogens, which are pathogens that can be inhibited in growth by the antibiotic.
These infections often include respiratory tract infections (such as pneumonia and bronchitis), throat, nasal, and ear infections (such as tonsillitis, sinusitis, and pharyngitis), and skin infections (such as wound infections, hair follicle/hair follicle infections, and erysipelas).
Use exactly as directed by your doctor or pharmacist. If used for too short or too long, there is a risk of resistance developing. This means that the bacteria become insensitive to clarithromycin. In addition, premature discontinuation of therapy may lead to a relapse.
Usually, clarithromycin is used in the form of tablets. For patients who have difficulty swallowing or are tube-fed, there is also a clarithromycin juice and a granulate for preparing a suspension for oral use.
Also available are tablets with a delayed release of active ingredient (sustained-release tablets). Unlike normal tablets, they only need to be taken once a day.
The usual duration of use varies from six to 14 days, depending on the severity of the infection. The dosage is usually 250 milligrams of clarithromycin twice daily. In severe infections, the doctor may double this dosage.
Clarithromycin should be used for the entire duration of treatment prescribed by the doctor. Even if the symptoms improve earlier, you should not discontinue it on your own (risk of development of resistance and relapse!).
What are the side effects of clarithromycin?
Side effects include insomnia, taste disturbances, headache, diarrhea, vomiting, nausea, digestive problems, altered liver values, increased sweating, and skin rash in one in ten to one in one hundred people treated.
The side effects in the digestive tract occur because the antibiotic also works against the beneficial intestinal bacteria. This impairs digestion and leads to the aforementioned symptoms.
What should be considered when taking clarithromycin?
Contraindications
Clarithromycin must not be taken in case of:
- concomitant use of any of the following drugs: ticagrelor (anticoagulant), ranolazine (for coronary heart disease), astemizole and terfenadine (antiallergic agents), cisapride and domperidone (prokinetic agents), and pimozide (antipsychotic).
- congenital or acquired QT interval prolongation
- severe liver dysfunction
Drug Interactions
Clarithromycin has interactions similar to other macrolide antibiotics, for example erythromycin. Since the drug is broken down in the liver by an enzyme (CYP3A4) that breaks down other drugs and also inhibits it, these drugs may interact with each other.
Thus, simultaneous intake (also at different times of the day) can result in too low or too high drug levels in the body. The drugs concerned then either have no effect at all or accumulate in the body to such an extent that toxic effects occur.
Examples of such active ingredients are:
- Oral diabetes drugs (antidiabetics) such as pioglitazone, repaglinide, rosiglitazone
- Statins (cholesterol-lowering drugs) such as lovastatin and simvastatin
- Migraine medicines such as ergotamine
- Antifungal medicines (antifungals) such as fluconazole, ketoconazole
- Heart medications such as digoxin, verapamil, nifedipine
- various HIV drugs such as ritonavir, efavirenz, nevirapine and etravirine, among others
- Antiepileptic drugs such as phenytoin, phenobarbital and valproic acid
- Oral contraceptives (“the pill”).
Because of the many drug interactions, let your doctor know which medications you are currently taking. Before using over-the-counter medications, inform your pharmacy that you are currently using clarithromycin.
Age Limitation
Clarithromycin may be used in newborns. The dosage is based on body weight. Elderly people may also take the antibiotic unless there is liver dysfunction.
Pregnancy and breastfeeding
If the doctor considers it absolutely necessary, the antibiotic may also be used during pregnancy and breastfeeding.
How to get medication with clarithromycin
How long has clarithromycin been known?
Clarithromycin was developed in the 1970s on the basis of the antibiotic erythromycin. A patent application for the active ingredient was filed in 1980 and it was marketed in Japan from 1991.
Later that year, the antibiotic was approved first in the United States and then worldwide. Patent protection expired in Europe in 2004 and in the U.S. in 2005, after which many manufacturers launched generic products containing the active ingredient clarithromycin.