ADMINISTRATION ROUTES:
PO, NG
ALTERNATIVE NAMES:
Arrow Roxithromycin
ICU INDICATIONS:
- Empirical treatment of atypical pneumonia
- Treatment of infections caused by other susceptible organisms
PRESENTATION AND ADMINISTRATION:
PO / NG:
Arrow Roxithromycin 150 mg tablets (white), 300 mg tablets (white)
Note: tablets may be crushed and administered via NG tube
DOSAGE:
PO / NG:
150 mg BD or 300 mg OD
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose as in normal renal function
DOSAGE IN PAEDIATRICS:
PO:
2.5 - 4 mg/kg BD
CLINICAL PHARMACOLOGY:
Roxithromycin is a semi-synthetic macrolide antibiotic derived from erythryomycin. It is bacteriostatic at low concentrations and bactericidal at high concentrations. It binds to the 50S subunit of the 70S ribosome, thereby disrupting bacterial protein synthesis. Roxithromycin is mostly secreted unchanged in bile with <10% excreted in urine. It has a half-life of 12 hours.
Roxithromycin is usually active against the following organisms both in vitro and in clinical infections:
- Streptococcus pyogenes (group A Beta-haemolytic streptococci)
- Alpha-haemolytic streptococci (viridans group)
- Staphylococcus aureus (resistant organisms may emerge during treatment)
- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Treponema pallidum
- Corynebacterium diphtheriae
- Corynebacterium minutissimum
- Entamoeba histolytica
- Listeria monocytogenes
- Neisseria gonorrhoeae
- Bordetella pertussis
- Legionella pneumophila (agent of Legionnaires' disease)
- Ureaplasma urealyticum
- Chlamydia trachomatis.
CONTRAINDICATIONS:
- Hypersensitivity to roxithromycin or other macrolide antibiotics
WARNINGS:
Hepatic dysfunction:
There have been reports of hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, occurring in patients receiving oral roxithromycin.
Pseudomembranous colitis:
Pseudomembranous colitis has been reported with nearly all antibacterial agents, including roxithromycin, and may range in severity from mild to life threatening. It is important to consider this diagnosis in patients who present with diarrhoea subsequent to the administration of antibacterial agents.
PRECAUTIONS:
General:
Caution should be exercised if roxithromycin is administered to patients with impaired hepatic function as its serum half life is increased in patients with hepatic failure. If administered to patients with severe hepatic insufficiency (e.g. hepatic cirrhosis with jaundice and/or ascites), the dose should be reduced by half to 150 mg OD.
Laboratory Tests:
No tests in addition to routine ICU tests are indicated
Drug/Laboratory Test Interactions:
None known
IMPORTANT DRUG INTERACTIONS IN ICU:
Roxithromycin has a much lower affinity for cytochrome P450 than erythromycin, and consequently has fewer interactions. Interactions may be observed however, with drugs that bind to alpha-1-acid glycoprotein, e.g. disopyramide.
Increases in prothrombin time (International Normalised Ratio - INR) have been reported in patients treated concomitantly with roxithromycin and warfarin.
Roxithromycin may increase the absorption of digoxin leading to increased serum levels.
ADVERSE REACTIONS:
General:
Anaphylaxis, angioedema
Gastrointestinal:
Nausea, vomiting, epigastric pain, diarrhoea, hepatitis
Dermatological:
Urticaria, rash, pruritus