Isoflurane is one of the safest and most accepted
anesthetic agents for reptiles, birds, and mammals. It has also been used in terrestrial amphibians. The use of inhalation agents in an entirely aquatic frog presents a new dilemma for delivery in contrast to terrestrial species. The African Clawed Frog respires by using both transcutaneous gas exchange and air breathing. These frogs remain submerged for long periods of time, thus making standard inhalation techniques impractical. We tested five methods for delivering
isoflurane: 1) bubbling
isoflurane and
oxygen in the water, 2) intracoelomic injection, 3)
subcutaneous injection, 4)
intramuscular injection, and 5) topical application. For the topical application, we developed a simple technique by using an absorptive pad with a vapor-barrier backing, saturating the pad with the liquid
isoflurane, and placing the pad on the back of the frog while it was confined in a
plastic bowl. Although two of the three
injectable routes induced
anesthesia, only the topical route produced rapid induction with consistent, safe recovery. Bubbling
isoflurane with
oxygen into water was unsuccessful. Topical application of
isoflurane was most successful and appears to be a safe and practical method that can be used as an alternative to
tricaine methylsulphonate,
hypothermia, or other methods for anesthetizing African Clawed Frogs.