Understanding pharmacodynamics in amphibians

Pharmacodynamics is the study of how drugs affect the body. In this interview, Jb Minter, DVM, MS, DACZM, director of animal health and chief veterinarian at the North Carolina Zoo in Asheboro, North Carolina, delves into this field of study in relation to amphibians, as part of a discussion on his lecture Navigating Amphibian Anesthesia and Analgesia, presented at the 2025 Fetch dvm360 conference in Charlotte, North Carolina.

Below is a partial transcript, lightly edited for clarity:

Jb Minter, DVM, MS, DACZM: So, pharmacodynamics in amphibians, again, very, very evolving field of study. So pharmacodynamics refers to the study of how drugs affect the body, including the mechanism of action, and the relationship... between the drug concentration and the effect of that drugs. So it's enhanced by a lot of different factors. So metabolism: amphibians have a low metabolic rate, and this is going to affect how the drugs are processed and eliminated, so got to take that into consideration.

The fact that they have permeable skin, so skin and amphibians is a key route for drug absorption. There's a lot of people that have looked at like topical drug absorption, so just dropping the drugs right on their back and how well it absorbs. So sometimes that can lead to faster onset of action. But also, there's been now some studies that have shown out there that obviously putting it on their back on certain species of amphibians don't really work at all, where you get this pretty varied absorption rate.

So there's a lot of species variation between how these drugs work and all of these different species. I said there are thousands of different species of amphibians. Now, not all of those are housed in human care or maintained by people that have pet amphibians and jumping what you may see in the literature for one species, the extrapolation between this frog and that frog, may not work as well as one may hope. So there's still a lot going on to the understanding that pharmacodynamics in amphibians requires some pretty careful attention, making sure that you're up to date on a lot of the literature and reaching out to friends and colleagues if you don’t really know the answer...