Roxithromycin is a semi-synthetic

macrolide Macrolides are a class of mostly natural products with a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. Macrolides belong to the polyketide class of natural products. ...

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

used to treat respiratory tract, urinary and soft tissue infections. It is a derivative of

erythromycin Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used ...

- comprising the same 14-membered lactone ring - with an

oxime In organic chemistry, an oxime is an organic compound belonging to the imines, with the general Chemical formula, formula , where R is an organic Side chain, side-chain and R' may be hydrogen, forming an aldoxime, or another organic functional g ...

-based

side chain In organic chemistry and biochemistry, a side chain is a substituent, chemical group that is attached to a core part of the molecule called the "main chain" or backbone chain, backbone. The side chain is a hydrocarbon branching element of a mo ...

attached to the macrolide ring. Roxithromycin was patented in 1980 and approved for medical use in 1987. It is available under several brand names in Australia, France, Germany, Israel, South Korea and New Zealand, but not in the United States. Roxithromycin has also been shown to possess antimalarial activity.

Side effects

The most common side effects are gastrointestinal: diarrhoea, nausea, abdominal pain and vomiting. Less common side effects include central or peripheral nervous system events such as headaches, dizziness, vertigo.Rarely seen side effects are rashes, abnormal liver function values and alteration in the senses of smell and taste.

Drug interactions

Roxithromycin has fewer interactions than

as it has a lower affinity for

cytochrome P450 Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for examp ...

. Roxithromycin is not known to interact with

hormonal contraceptives Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original ...

prednisolone Prednisolone is a corticosteroid, a steroid hormone used to treat certain types of allergies, inflammation, inflammatory conditions, autoimmune disorders, and cancers, Electrolyte imbalance, electrolyte imbalances and skin conditions. Some of ...

carbamazepine Carbamazepine, sold under the brand name Tegretol among others, is an anticonvulsant medication used in the treatment of epilepsy and neuropathic pain. It is used as an adjunctive treatment in schizophrenia along with other medications and as ...

ranitidine Ranitidine, previously sold under the brand name Zantac among others, is a medication used to decrease stomach acid production. It was commonly used in treatment of peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellis ...

antacids An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts o ...

. When roxithromycin is administered with

theophylline Theophylline, also known as 1,3-dimethylxanthine, is a drug that inhibits phosphodiesterase and blocks adenosine receptors. It is used to treat chronic obstructive pulmonary disease (COPD) and asthma. Its pharmacology is similar to other met ...

, some studies have shown an increase in the plasma concentration of

. A change in dosage is usually not required but patients with high levels of

at the start of the treatment should have their plasma levels monitored. Roxithromycin appears to interact with

warfarin Warfarin, sold under the brand name Coumadin among others. It is used as an anticoagulant, anticoagulant medication. It is commonly used to prevent deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who ha ...

. This is shown by an increase in prothrombin time and/or international normalised ratio (INR) in patients taking roxithromycin and

concurrently. As a consequence, severe bleeding episodes have occurred.

Available forms

Roxithromycin is commonly available as tablets or oral suspension.

Mechanism of action

Roxithromycin prevents

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

from growing, by interfering with their

protein synthesis Protein biosynthesis, or protein synthesis, is a core biological process, occurring inside cells, balancing the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a number of critica ...

. Roxithromycin binds to the subunit 50S of the bacterial

ribosome Ribosomes () are molecular machine, macromolecular machines, found within all cell (biology), cells, that perform Translation (biology), biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order s ...

, and thus inhibits the synthesis of

peptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...

s. Roxithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly ''

Legionella pneumophila ''Legionella pneumophila'', the primary causative agent for Legionnaires' disease, Legionnaire's disease, is an Aerobic organism, aerobic, pleomorphic, Flagellum, flagellated, non-spore-forming, Gram-negative bacteria, Gram-negative bacterium. ' ...

''.

Pharmacokinetics

When taken before a meal, roxithromycin is very rapidly absorbed, and diffuses into most tissues and

phagocyte Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s. Due to the high concentration in

phagocytes Phagocytes are cell (biology), cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or Apoptosis, dying cells. Their name comes from the Greek language, Greek ', "to eat" or "devour", and "-cyte", the suffix in ...

, roxithromycin is actively transported to the site of infection. During active phagocytosis, large concentrations of roxithromycin are released.

Metabolism

Only a small portion of roxithromycin is metabolised. Most of roxithromycin is secreted unchanged into the bile and some in expired air. Under 10% is excreted into the urine. Roxithromycin's half-life is 12 hours.

History

French pharmaceutical company

Roussel Uclaf Roussel Uclaf S.A. was a French pharmaceutical company and one of several predecessor companies of today's Sanofi. It was the second largest French pharmaceutical company before it was acquired by Hoechst AG of Frankfurt, Germany in 1997, with p ...

first marketed roxithromycin in 1987.

References

External links

* {{Portal bar , Medicine Macrolide antibiotics Ketoxime ethers Dimethylamino compounds