Quinupristin + Dalfopristin

Intravenous
Complicated skin and skin structure infections

Intravenous
Vancomycin-resistant Enterococcus faecium

Dosage adjustment may be required.

Single dose vial: Reconstitute with 5% dextrose in water or sterile water for inj. Swirl gently (without shaking) to dissolve. Allow the solution to sit for a few minutes until all the foam has disappeared. Resulting solution should be clear and yield a concentration of 100 mg/mL. Based on patient's wt, reconstituted solution should be added to 250 mL of 5% dextrose in water for peripheral admin (may increase to 500 mL or 750 mL to limit venous irritation). An infusion volume of 100 mL may be used for central line infusions.

Incompatible with saline.

Severe hepatic impairment. Hypersensitivity.

Hepatic impairment and predisposition to cardiac arrhythmias.

Nausea, vomiting, diarrhoea, headache, arthralgia, myalgia, asthenia, rash, pruritus, anaemia, leucopenia, eosinophilia, raised urea and creatinine; inj-site reactions on peripheral venous administration; less frequently oral candidiasis, stomatitis, constipation, abdominal pain, anorexia, peripheral oedema, hypotension, chest pain, arrhythmias, dyspnoea, hypersensitivity reactions (including anaphylaxis and urticaria), insomnia, anxiety, confusion, dizziness, paraesthesia, hypertonia, hepatitis, jaundice, pancreatitis, gout; also reported, thrombocytopenia, pancytopenia, electrolyte disturbances.
Potentially Fatal: Pseudomembranous colitis.

Parenteral: B

Signs may include dyspnoea, emesis, tremors and ataxia. Careful observation and supportive treatment are recommended.

Increased risk of ventricular arrhythmias when used with drugs that prolong QT interval eg. astemizole, cisapride and terfenadine. May increase the serum levels of ciclosporin, nifedipine, midazolam and tacrolimus.

Description: Quinupristin/Dalfopristin works synergistically to inhibit bacterial protein synthesis by binding at different sites on the 50S subunit of the bacterial ribosome. Quinupristin works by inhibiting peptide chain elongation in the late phase of protein synthesis while dalfopristine works by inhibiting the peptidyl transferase in the early phase of protein synthesis.
Pharmacokinetics:
Distribution: Plasma protein binding: 55-78% (quinupristin) and 11-26% (daflopristine).
Metabolism: Rapidly metabolised in the liver.
Excretion: Biliary excretion is probably the primary route for faecal elimination. 75-77% of a dose is excreted faecally. Half-life of quinupristin and its metabolites: about 3 hr, half-life of daflopristin and its metabolites: about 1 hr.

Unopened vial: Store at 2-8°C (36-46°F). Reconstituted solution should be diluted within 30 minutes. Stability of the diluted solution prior to the infusion is established as 5 hr at room temperature or 54 hr if refrigerated at 2-8°C (36-46°F). Do not freeze solution.

Antibacterial Combinations