Intravenous Infusion

One Compartment Linear Model

Student Objectives for this Chapter

• To draw the schemes and write the differential equations for a one compartment pharmacokinetic model after IV infusion administration
• To recognize and use the integrated equation for drug concentrations during and after an IV infusion administration
• To calculate kel and V from IV infusion data
• To design and calculate appropriate IV infusion (IV infusion alone, fast/slow IV. infusion, or infusion/bolus) dosage regimens

Commonly in a hospital setting a patient will receive a drug by intravenous infusion. The inconvenience of administering the drug over a long time is not a real problem with bedridden patients. Some may already be receiving intravenous fluids. If a drug is chemically stable and is compatible with the intravenous fluid it may be added to the fluid and thereby be given by slow infusion.

Some drugs cannot be given by rapid intravenous injection. Therefore they may be given by slower IV infusion over 15 or 30 minutes. For example, IV phenytoin must be given slowly, no greater than 50 mg/min (and preferably 25 mg/min or less) in adults. Much slower in neonates. Phenytoin's poor solubility requires alkaline pH control and/or a co-solvent which can produce adverse effects when given too quickly.

• Dosing instructions from Virtual Hospital
• Dosing Information from Abbott India

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Copyright 2001-3 David W. A. Bourne (david@boomer.org)