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.
Copyright 2001 David W.A. Bourne