The active medical ingredient clarithromycin is a macrolide antibiotic. The drug is primarily used for the treatment of bacterial respiratory tract infections.
What is clarithromycin?
The active medical ingredient clarithromycin is a macrolide antibiotic. The drug is primarily used for the treatment of bacterial respiratory tract infections. Clarithromycin belongs to the group of macrolide antibiotics. It causes inhibition of translocation and interferes with the protein synthesis of bacteria, which is how it achieves its bacteriostatic efficacy. A typical characteristic of macrolides is that they act intracellularly and belong to the broad-spectrum antibiotics. Clarithromycin was developed in the 1970s by the Japanese company Taisho Pharmaceutical. The antibiotic erythromycin served as a model for the drug. The drug was finally patented in 1980. However, it took until 1991 for the drug to be marketed in Japan, and in the same year it was also launched in the USA. This was followed by approval throughout the world. Clarithromycin’s patent protection ended in Europe in 2004, after which numerous generics containing the macrolide antibiotic were released.
Pharmacologic action
Clarithromycin has the property of slowing down the multiplication of bacteria. For this purpose, the active ingredient penetrates the bacterial cells. There, it ensures that the germs can no longer produce proteins (albumin). This inhibition of bacterial growth ultimately causes the human defense system to push back the infection caused by the bacteria. Unlike erythromycin, clarithromycin can exert its effect against even more bacteria. Thus, it is effective against both air-breathing (aerobic) and non-air-breathing (anaerobic) strains of Gram-negative and Gram-positive bacteria. Furthermore, the antibiotic is stable to gastric acid and therefore cannot break down in the stomach. Because it is also more tissue accessible, it can reach its target sites more effectively. For this reason, clarithromycin achieves a better efficacy than erythromycin at the same dosage, despite its lower bactericidal properties. The absorption of clarithromycin into the human intestine takes place after a short time. From there, the macrolide antibiotic enters the blood. Partial metabolism of the drug occurs in the liver. Excretion of clarithromycin from the body occurs about four hours after its absorption. In this process, 75 percent of the antibiotic leaves the body through the stool and 25 percent through the urine.
Medical application and use
Clarithromycin is used against infections with bacteria that are sensitive to macrolide antibiotics. In this context, the drug can be administered against respiratory infections such as bronchitis or pneumonia, inflammation of the sinuses, pharyngitis, tonsillitis, wound infections, erysipelas, and hair follicle inflammation. Other indications include abscesses, impetigo, and gastric and duodenal ulcers caused by the bacterium Helicobacter pylori. The drug is used together with metronidazole, amoxicillin or omeprazole. Clarithromycin is also used when more efficient antibiotics cannot be administered, for example because the patient is intolerant to them. This also applies if the pathogens are resistant to the other antibiotic. This is usually the case in moderately severe skin infections or tonsillitis caused by streptococci. Clarithromycin is usually administered by tablets. However, if necessary, the antibiotic can also be administered in the form of infusions or injections if patients have difficulty swallowing. Alternatively, clarithromycin can also be taken as a juice or granules. There are also sustained-release tablets, which release the active substance more slowly. In this case, the patient only needs to take the drug once a day. The duration of clarithromycin treatment is usually 6 to 14 days, depending on the extent of the disease. The recommended dose is 250 milligrams of clarithromycin twice a day. However, if necessary, the doctor may increase the dose by double.If symptoms improve, clarithromycin must still be taken until the end of the prescribed therapy to counteract possible relapses.
Risks and side effects
Some patients may experience unpleasant side effects from taking clarithromycin. These mainly include temporary discoloration of the tongue, disturbances in the sense of smell, taste disturbances, nausea, vomiting, gastrointestinal symptoms such as stomach pressure, bloating, or abdominal pain, headache, and a fungal infection in the mouth. Occasional side effects include temporary hearing loss, tinnitus, hives, itching, skin rashes, joint swelling, facial swelling, liver function disorders, jaundice (icterus), biliary congestion, and seizures. Side effects in the gastrointestinal tract are due to the fact that beneficial intestinal bacteria are also affected by clarithromycin. This may cause digestive problems. Clarithromycin should not be used if the patient suffers from hypersensitivity to the active substance or other macrolide antibiotics. It is also not allowed to take the drug in case of low potassium level. Otherwise, there is a risk of life-threatening cardiac arrhythmias. The same applies to a slowed excitation recovery of the heart. Clarithromycin may also be taken during pregnancy only with the permission of the physician. The safety of the antibiotic in pregnancy has not yet been confirmed. During breastfeeding, the drug can pass into the mother’s milk and thus into the baby’s body, sometimes resulting in diarrhea or intestinal inflammation. The simultaneous use of other macrolide antibiotics and clarithromycin leads to the active substance being inhibited in its activity. In addition, the bacteria often no longer respond to the antibiotics taken and become resistant to clarithromycin.
