The FDA this week issued a safety alert to remind producers, veterinarians and health-care providers of potential safety hazards in using Micotil 300 (tilmicosin). Micotil 300 is a prescription injectable antibiotic used to treat respiratory disease in cattle and sheep.

Human exposure to Micotil 300, particularly through accidental injection, can lead to toxicity to the cardiovascular system. According to theFDA, injections of less than 0.5 ml (1/10 teaspoon) have been associated with pain and bleeding at the injection site, while larger volumes have been associated with nausea, dizziness, rapid heart rate, and death. Oral or skin exposure also has resulted in toxicity, but injections pose the greatest risk of severe injury or death.

These risks have been well-known for years, and of the 25 known deaths associated with the drug, the FDA says the “majority of the deaths were due to intentional self administration of the drug.” Some deaths have, however, resulted from accidental injections.

FDA recommends regular training for workers who administer Micotil 300 to livestock. Do not use in the product in automatically powered syringes and avoid contact with eyes. In the case of accidental self-injection, consult a physician immediately and apply ice or cold pack to injection site. Emergency medical telephone numbers are 1-800-722-0987 or 1-800-428-4441.

While there is no antidote for Micotil poisoning, FDA notes research has shown cardiovascular toxicity may be due to calcium channel blockade. In dogs, administration of intravenous calcium offset Micotil-induced tachycardia and negative inotropy (decreased contractility). Dobutamine partially offset the negative inotropic effects induced by Micotil in dogs. β-adrenergic antagonists, such as propranolol, exacerbated the negative inotropy of Micotil in dogs. In pigs, tests have indicated administration of epinephrine increased the risk of fatality.

FDA notes that Elanco Animal Health, which distributes Micotil 300, “has made efforts to warn and educate people about the human health risks associated with this product and to provide training to users and veterinarians on safe handling and use of Micotil 300.” Elanco is currently working in consultation with the FDA to further address this issue.

Read more from the FDA.