During the 1960s and early 1970s, while working for Ohio Medical Products, chemists Louise Speers Croix, PhD (1920-1992), and Ross C. Terrell, PhD (1925-2010) systematically synthesized several hundred new fluorinated compounds. Four of these became inhalation anesthetics, including isoflurane (Forene). Inhalation anesthetics are inhaled into the lungs and transported throughout the body via the blood stream. When they reach the brain, they produce the loss of consciousness and general insensibility to pain we call anesthesia.

When Drs. Croix and Terrell began their research, the most popular inhalation anesthetic was halothane. Halothane was an effective anesthetic but questions of its safety had been raised. Clinical trials of isoflurane demonstrated that it was not only relatively safe and effective but that it produced anesthesia more quickly than halothane. Likewise, the effects of anesthesia faded faster, and with little postoperative nausea. Isoflurane received FDA approval for clinical use in 1981. Two of the other inhalation anesthetics synthesized by Drs. Croix and Terrell, sevoflurane and desflurane, slowly gained preference over isoflurane.

In the 1970s, some inhalation agents, including isofluane, were shown to deplete the ozone layer. These were replaced in the 1990s with desflurane and sevoflurane, agents that do not impact the ozone layer.

Catalog Record: Isoflurane Catalog record unavailable.