How Roxithromycin works
Like all macrolide antibiotics, Roxithromycin also blocks bacterial protein synthesis. In this way, the growth and reproduction of bacteria is inhibited (bacteriostatic effect).
Just like animal and human cells, bacterial cells also have genetic material (DNA) that serves as a blueprint for the proteins that fulfill numerous tasks in the cell. Roxithromycin inhibits the so-called ribosomes, i.e. the complexes in the cell in which proteins are formed according to the DNA blueprint.
As the ribosomes of bacteria and humans differ greatly, roxithromycin can be used to precisely switch off the bacterial ribosome. In contrast, the antibiotic has comparatively few (side) effects on human cells.
Absorption, breakdown and excretion
After ingestion, two thirds of Roxithromycin is quickly absorbed into the blood via the intestinal wall, where it reaches its highest levels after two hours.
The antibiotic reaches the lungs, skin and urinary tract particularly well via the bloodstream. It also accumulates in immune cells, which actively migrate to the site of a bacterial infection via the bloodstream.
When is Roxithromycin used?
Roxithromycin is used to treat bacterial infections with susceptible pathogens, such as
- Ear, nose and throat infections
- Infections of the lungs
- Infections of the skin
- Infections of the urinary tract
Roxithromycin is taken for a limited period of time and according to the doctor’s instructions. Even if the symptoms subside beforehand, the therapy must be continued until the end. Otherwise the infection may flare up again.
How Roxithromycin is used
Roxithromycin is taken in the form of tablets. The amount of active ingredient and the duration of treatment depend on the type and severity of the infection, the patient’s condition and the sensitivity of the pathogen.
The usual dosage for adults is 150 milligrams of Roxithromycin twice a day at intervals of around twelve hours before meals. The total daily dose is therefore 300 milligrams.
Children under 40 kilograms body weight and patients with liver damage receive a reduced dosage.
The duration of therapy is usually between five days and two weeks.
What are the side effects of Roxithromycin?
In one in one hundred to one thousand patients, there is an increase in white blood cells (leukocytes), hypersensitivity reactions and a skin rash with itching.
Rarely, a so-called superinfection with yeast fungi (Candida) develops on the oral or vaginal mucosa, as the “good” bacteria are also killed by Roxithromycin – fungi can then spread more easily.
What should I bear in mind when taking Roxithromycin?
Contraindications
Roxithromycin must not be used in the following cases
- hypersensitivity to the active substance or any of the other ingredients of the medicine
- concomitant administration of ergot alkaloids (e.g. older migraine medications)
- concomitant administration of substances that are metabolized by the enzyme CYP3A4 and have a narrow therapeutic range (= the interval between effective and toxic dosage is very small)
Particular caution is also required if drugs that can prolong the QT interval in the heart (visible in the ECG) are taken at the same time.
Interactions
Roxithromycin influences the heart rhythm by causing a so-called QT prolongation. The simultaneous administration of other active substances that also have this property can lead to serious cardiac arrhythmias.
Such active substances include, for example, certain drugs for depression (such as citalopram, amitriptyline, imipramine), opioid painkillers (such as methadone), drugs for psychosis and schizophrenia (such as chlorpromazine, perphenazine, zuclopenthixol), antibiotics (such as moxifloxacin), agents against viral infections (such as telaprevir), antifungal agents (such as fluconazole) and agents against protozoal infections (such as pentamidine) as well as agents against cardiac arrhythmias (such as quinidine, procainamide, amiodarone).
Roxithromycin increases the absorption of the cardiac drug digoxin, which can increase its side effects. The serum level of digoxin (and other cardiac glycosides) should therefore be monitored during combined treatment. The situation is similar with theophylline (reserve drug for COPD) and the Parkinson’s drug bromocriptine.
Age restriction
There is no experience with the use of Roxithromycin in children and adults under 40 kilograms body weight.
Pregnancy and breastfeeding
During pregnancy, Roxithromycin should only be taken after a strict risk-benefit assessment, even though animal studies have not shown any harmful effects on the unborn child.
Although only a very small proportion of Roxithromycin passes into breast milk, the prescribing information advises not to take the antibiotic while breastfeeding or to discontinue breastfeeding for the duration of the intake.
However, clinical experience has so far shown no relevant side effects in breastfed children whose mothers have taken Roxithromycin. According to experts, the active ingredient can therefore be used according to indication and without interrupting breastfeeding.
How to obtain medication with Roxithromycin
Roxithromycin is only available on prescription in Germany and Austria. The active ingredient is no longer on the market in Switzerland.
How long has Roxithromycin been known?
Roxithromycin was launched in 1987 and represents a targeted further development of the antibiotic erythromycin. Thanks to chemical changes, Roxithromycin has fewer interactions, has a broader spectrum of activity against bacteria, is less sensitive to stomach acid and can therefore be better taken as a tablet.
