Drugs in this class are used for: Treatment and/or prophylaxis of infections.
Erythromycin is one of the main macrolides. It has an antibacterial spectrum similar to penicillins, which is why it has become a useful alternative to people allergic to penicillins. However, because of increasing resistance, erythromycin is used only in short courses. Erythromycin inhibits protein synthesis by interrupting bacterial ribosomal function. Erythromycin has a shorter half life than clarithromycin and azithromycin, meaning more frequent dosing as well as more gastro-intestinal side effects. Telithromycin is used mostly against penicillin- and erythromycin-resistant Streptococcus pneumonia.
Dosage regimen
(N.B. *Refer to SPC for dosage details for neonates, infants and specific infections)
250-500mg every six hours or 0.5-1g every 12 hours. Up to 4g daily in divided doses in severe infections.*
By IV infusion, adult and child: severe infections, 50mg/kg daily by continuous infusion or in divided doses every six hours. Mild infections, 25mg/kg daily. *
Azithromycin
·Active against some Gram-negative organisms (eg H. influenzae)
·Lyme disease
·RTI (eg otitis media)
·Skin and soft tissue infections
·Uncomplicated genital chlamydia infections
·Non-gonococcal urethritis
·Prophylaxis of group A streptococcal infections
By mouth:
500mg once daily for three days or 500mg on first day then 250mg once daily for four days. *
Clarithromycin
·RTIs
·Mild to moderate skin and soft tissue infections
·Otitis media
·Part of Helicobacter pylori eradication (used in conjunction with a proton pump inhibitor and metronidazole)
By mouth:
250mg every 12 hours for seven days increased in severe infections to 500mg every 12 hours for up to 14 days.*
By IV infusion: into larger proximalvein, 500mg twice daily.*
Telithromycin
·Beta-haemolytic streptococcal pharyngitis and tonsillitis
·Sinusitis
·Community acquired pneumonia
·Exacerbations of chronic bronchitis (caused by organisms resistant to beta-lactam antibacterials and other macrolides)
By mouth:
For sinusitis, exacerbations of chronic bronchitis,pharyngitis or tonsillitis, 800mg once daily for five days. *
For community acquired pneumonia, 800mg once daily for seven to10 days. *
Patient’s knowledge of the medicine’s use Patients should be: • Given appropriate counselling regarding their antibiotics. • Advised of any potential side effects and any drug interactions with existing medicines. (NB macrolides, especially erythromycin, are mostly metabolic inhibitors of other drugs leading to high risk of reaching toxic levels. So while on this medication dosing may need to be adjusted accordingly). • If taking telithromycin, give information about alarming symptoms that can develop in liver disorders.
Is the medicine working? • Most infections require short courses of antibiotics but if infections are recurrent perhaps compliance to medicines needs to be analysed. • Indigestion remedies must not be taken at the same time of day as any macrolide. • Azithromycin must be taken on an empty stomach whereas clarithromycin must be taken with/after food. • Assess possible swallowing difficulties so that syrup forms can be acquired.
Side effects • Hypersensitivity reactions (eg rashes, anaphylaxis). • Gastro-intestinal disturbances (eg nausea, vomiting, abdominal discomfort and diarrhoea). • Telithromycin can also cause visual disturbances, flatulence, taste disturbances, dizziness and headaches.
Lifestyle This will largely depend on the type of infection. • Maintain a varied, healthy diet to build up the immune system. Ensure adequate hydration (especially in the elderly and children). • Patients should be aware of all possible symptoms in case infection relapses. • Encourage compliance to minimise risk of antibiotic resistance.
Anita Bagga is a community pharmacist from Leicester
