Intravenous Infusions

Abstract

Intravenous infusions are being used with increasing frequency in modern medicine. There are a variety of reasons for this.

• Administration of drugs by intravenous infusion enables a constant plasma drug con- centration to be maintained. This is especially important with drugs whose therapeutic concentration range is narrow. The plasma concentrations of such drugs when administered as intermittent intravenous boluses are frequently in the toxic range, or too low to be therapeutic. An example of such a drug is theophylline. Theophylline has a minimum therapeutic plasma concentration of 10 mg/L and a minimum toxic plasma concentration of 20 mg/L [5].

• The dose per unit time of a drug administered by continuous intravenous infusion is lower than if the same drug had been administered intermittently. An example of this is provided by the total dose of midazolam required to maintain hypnosis for a given time. The total dose required to maintain hypnosis is lower when midazolam is administered by constant intravenous infusion, than when administered as intermittent intravenous bolus doses [1].

• Accurate electronically controlled intravenous infusion pumps are becoming increasingly more available in most modern hospitals. These make the administration of drugs by intravenous infusion much easier.