Compatibility of diazepam with intravenous fluid containers and administration sets

The effect of i.v. containers (plastic and glass) and plastic administration sets (with and without inline filters) on diazepam availability was studied. Solutions (50 mg diazepam/500 ml fluid and 25 mg/500 ml) of diazepam in dextrose 5% in water and lactated Ringer's injection were stored in glass i.v. bottles or plastic burette chambers and then infused (2.5 and 5 mg/hr) through plastic i.v. administration sets with or without 0.45-micron inline filters. Concentrations of the solutions were measured spectrophotometrically after two and four hours in the containers and in the administration sets. Solutions were inspected visually for compatibility, and pH was measured. No visual incompatibilities were observed, and pH remained constant. Solutions stored in glass bottles and infused through plastic sets retained greater than 90% of initial potency after four hours. Solutions stored in plastic burette chambers and administered through plastic sets lost greater than 38% of potency after two hours; the loss occurred principally in the plastic chamber and increased with increasing drug concentration and time. Drug availability was not affected by type of i.v. fluid, pH, flow rate, or filtration. If diazepam is to be infused, it should be diluted to at least a 1:10 dilution in glass i.v. bottles and administered through plastic administration sets not having burette chamgers. Inline filters (0.45 micron) may be used without a loss of potency.