Preamble: Stanford points out that the average 70-year-old is on 7 (seven) pharmaceutical agents1. Since literally hundreds of potential adverse reactions can occur with each medication, imagine the potential for cross reactivity (same reference quotes an average number of potential side effects per drug to be 69)…especially if a drug’s metabolite can impart adverse reactions too? The major difference in the above two delivery mechanisms is called the "first pass effect."2,3 Hepatic and intestinal tissues metabolize or degrade a pharmaceutical’s actions and lead to a reduction of efficacy or an increase in unwanted metabolites. A dermal delivery minimizes this "first pass" through these tissues. Further, many molecules simply cannot pass through the gauntlet of the intestinal tract at all…hence the need to deliver the molecule insulin by injection. One last thought on this topic would be site specific delivery of a pharmaceutical such as Herpes Zoster (shingles pain), psoriasis (localized dermal conditions), and insect bites or incisional pain. These regional conditions would be better served to manage the site of interest while minimizing exposure of the rest of the body to the medicinal agent.

 

1http://med.stanford.edu/news/all-news/2012/03/scientists-discover-multitude-of-drug-side-effects-interactions-using-new-computer-algorithm.html
2http://www.ncbi.nlm.nih.gov/pubmed/6362950
3http://www.drugs.com/dict/first-pass-metabolism.html