Hazardous Drugs as a Veterinary Workplace Hazard

Veterinary occupational exposure to hazardous drugs involves unintended contact with medications that pose health risks. Such drugs include chemotherapy agents, antivirals, hormones, certain biologics, and other pharmaceuticals.

The US National Institute for Occupational Safety and Health (NIOSH) defines a hazardous drug as a drug approved for use in humans that is associated with carcinogenicity, teratogenicity, reproductive toxicity, organ toxicity at low doses, genotoxicity, or similarity to known hazardous compounds (1).

Because of the associated health risks, such drugs require specialized handling procedures to protect veterinary personnel.

Exposure to hazardous drugs can occur at multiple points, including drug preparation and administration, aerosol generation, spills, accidental injection, contact with treated animals or their body fluids (such as urine, feces, or saliva), and improper waste disposal. The primary routes of exposure are skin contact (the most common), inhalation of aerosols or particles, ingestion via contaminated hands or food, and accidental injection via needle sticks.

For instance, accidental self-injection with the macrolide antimicrobial tilmicosin has been linked to serious cardiac effects, such as tachycardia, arrhythmias, and sudden death. Similarly, accidental exposure to potent opioid agents like carfentanil and etorphine—used in wildlife immobilization—can lead to severe respiratory depression, unconsciousness, and death (2).

Whenever these opioids are used, the antidote (naloxone) should be immediately available, and another individual trusted to administer this antidote should be present, in case the person injecting any of these potentially deadly, fast-acting opioids is accidentally pricked with a needle. Accidental exposure to these and other veterinary drugs is an ongoing public health concern (3).

The severity and type of adverse effects of exposure to these hazardous drugs depend on the drug class and level of exposure. Both acute high-dose exposure and chronic low-dose exposure are important occupational concerns. Health effects can include skin irritation, allergic reactions, nausea, and other short-term symptoms, as well as long-term consequences such as infertility, miscarriage, congenital abnormalities, increased cancer risk, and organ toxicosis.

Examples of hazardous drugs that are commonly encountered in veterinary practice are summarized in the table Select Hazardous Drugs of Concern in Veterinary Practice.

The main strategy for managing hazardous drugs in a veterinary clinic is to minimize exposure. Methods to decrease occupational risk include preparing medications in biological safety cabinets and using closed-system drug transfer devices to limit leaks, spills, and vapor release (4). Personal protective equipment (PPE)—such as gloves, gowns, and eye protection—should always be worn during drug preparation, handling, and administration.

To lower the risk of accidental needle sticks, staff should avoid recapping needles, use safety-engineered devices (such as retractable or shielded needles and blunt-tip systems), and ensure proper animal restraint. Comprehensive training in safe drug handling and animal management—particularly when working with large animals or wildlife—also plays a critical role in decreasing exposure. In addition, all hazardous drugs should be clearly labeled, and access to high-risk medications should be restricted within the veterinary clinic.