Chapter 7 Routes of Drug Administration

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Intravenous (IV)

Drugs may be given into a peripheral vein over 1 to 2 minutes or longer by infusion. Rapid injections are used to treat epileptic seizures, acute asthma, or cardiac arrhythmias.

Figure 7.5.1 Showing IV, IM, and SC Injection

Advantages:

Rapid - A quick response is possible. Plasma concentration can be precisely controlled using IV infusion administration.

Total dose - The whole dose is delivered to the blood stream. That is the bioavailability is generally considered to 100% after IV administration. Larger doses may be given by IV infusion over an extended time. Poorly soluble drugs may be given in a larger volume over an extended time period.

Veins relatively insensitive - to irritation by irritant drugs at higher concentration in dosage forms.

Disadvantages:

Suitable vein - It may be difficult to find a suitable vein. There may be some tissue damage at the site of injection.

Maybe toxic - Because of the rapid response, toxicity can be a problem with rapid drug administrations. For drugs where this is a particular problem the dose should be given as an infusion, monitoring for toxicity.

Requires trained personnel - Trained personnel are required to give intravenous injections.

Expensive - Sterility, pyrogen testing and larger volume of solvent means greater cost for preparation, transport and storage.

Figure 7.5.2 Typical Plot of Cp versus Time after IV Bolus Administration

Figure 7.5.3 Typical Plot of Cp versus Time during an IV Infusion Administration

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