Pristinamycin is an antibiotic medication used to address various bacterial infections. It belongs to a class of antibiotics that work by inhibiting the growth of harmful bacteria. This medication is typically considered when other common antibiotics may not be effective.
How Pristinamycin Works
Pristinamycin interferes with bacterial protein synthesis. As a streptogramin antibiotic, it binds to specific parts of the bacterial ribosome, the cellular machinery responsible for building proteins. It is composed of two synergistic components: Pristinamycin I (a streptogramin B antibiotic) and Pristinamycin II (a streptogramin A antibiotic).
Both components bind to the 50S subunit of the bacterial ribosome. This binding action prevents bacteria from creating the proteins they need to grow and multiply. While each component alone has a moderate effect, their combined action is synergistic, leading to a much more potent bactericidal (bacteria-killing) activity, potentially increasing effectiveness by up to 100 times compared to individual components. This coordinated action halts bacterial proliferation, allowing the body’s immune system to clear the infection.
Infections Treated by Pristinamycin
Pristinamycin treats specific bacterial infections, especially those caused by Gram-positive bacteria resistant to other common antibiotics. It is effective against resistant strains like Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococci (VRE). It also has a broad range of activity against many Gram-positive cocci, and certain other bacteria including:
Clostridium
Haemophilus
Neisseria
Chlamydia
Ureaplasma species
It is used in severe skin and soft tissue infections involving resistant bacterial strains. It is also used for bone and joint infections, particularly those involving prosthetic joints with resistant Staphylococcus aureus or coagulase-negative staphylococci. While less sensitive to enterococcal species, many enterococci resistant to streptogramin B can still be susceptible to pristinamycin’s combined agents.
Important Considerations for Use
Pristinamycin is administered orally, usually as tablets. Dosing varies by infection, but a common regimen is two 500mg tablets four times daily for 10 days. For deep-seated infections, a dose of 2 grams every 12 hours may be considered. It is recommended to take tablets with food and water. If swallowing is difficult, they can be crushed in milk or soft food. Intravenous formulations are not available due to poor solubility, limiting its use for severe infections.
Pristinamycin can cause side effects. Common side effects include gastrointestinal issues like nausea, vomiting, and diarrhea, and skin rashes. These are usually mild and improve within a few days. More serious, less common side effects include severe watery diarrhea (potentially indicating pseudomembranous colitis) or yellowing of the skin or eyes (suggesting liver toxicity). Seek medical advice if any severe reactions develop.
Pristinamycin can interact with other medications, altering their effects or increasing side effect risk. It can increase serum levels of certain immunosuppressants, such as ciclosporin. Other interactions include colchicine (for gout), certain blood thinners (like vitamin K antagonists), and other immunosuppressing medicines. Inform healthcare providers about all current medications, including over-the-counter drugs, herbal remedies, and supplements, to avoid potential interactions.
Pristinamycin should not be used in specific situations. Individuals with a known allergy to streptogramin antibiotics or any components of pristinamycin should avoid it. Patients with severe liver impairment may also be advised against its use. It is not recommended during pregnancy or breastfeeding; discuss these considerations with a healthcare provider.