WARNING! Transdermal drug pointers
Topical medications may cause skin irritation, such as pruritus and a rash. Watch for these symptoms and for adverse reactions to the specific medication.
A few examples
Transdermal nitroglycerin medications may cause headaches and, in elderly patients, orthostatic hypotension. Nitroglycerin ointment can be applied to chest area, abdomen, and front of thigh or back.
Know what the drug is that you are administering and be alert to its effects, implications, and adverse reactions.