PHAR 4634 - Chapter 7 Page 5


This involves administration of the drug dose just under the skin.


Can be given by patient, e.g. in the case of insulin

Absorption slow but usually complete. Improved by massage or heat. Vasoconstrictor may be added to reduce the absorption of a local anesthetic agent, thereby prolonging its effect at the site of interest.


Can be painful

Irritant drugs can cause local tissue damage

Maximum of 2 ml injection thus often small doses limit use.



Larger volume, than sc, can be given by IM

A depot or sustained release effect is possible with IM injections, e.g. procaine penicillin


Trained personnel required for injections. The site of injection will influence the absorption, generally the deltoid muscle is the best site

Absorption is sometimes erratic, especially for poorly soluble drugs, e.g. diazepam, phenytoin. The solvent maybe absorbed faster than the drug causing precipitation of the drug at the site of injection.

This page was last modified: 12 February 2001

Copyright 2001 David W.A. Bourne