Insights on Topical and Transdermal Medications

The transdermal formulations of fentanyl and buprenorphine are for patients who have chronic pain. An important distinction is, with transdermal fentanyl the patient has to be opioid tolerant, on the equivalent of 60 mg of oral morphine a day for at least a week, whereas with transdermal buprenorphine that’s not the case. Remember too, that fentanyl is a very fat soluble drug and it’s not uncommon for us to have a patient in hospice who weighs 70 or 80 pounds. They just don’t have enough fat to hold on to the drug. Also, you want to be careful in using a transdermal system in someone whose pain picture is escalating or changing fairly quickly. These are delivery systems that take three to six days to achieve steady state so you can’t chase that pain with such a long-acting delivery system.

With topical products, the topical nonsteroidals are a valuable class of drugs that have been introduced to the market over the past couple of years. For a patient with pain in their knee or their elbow, you can apply topically right to the site of where the pain is. These drugs are not used for systemic absorption. You get good synovial fluid levels right there where the pain is but you’re not going to get to systemic levels, which is good and bad. The upside is you’re far less likely to suffer adverse effects. This is a localized therapy that has been very beneficial in patients who could not otherwise take systemic nonsteroidal therapy because of either the cardiac risk or the risk to their gastrointestinal system.