Thiafentanil

Indications

For immobilization of captive minor species hoof stock, excluding any member of a food-producing minor species such as deer, elk or bison and any minor species animal that may become eligible for consumption by humans or food-producing animals. Use only when there is a reasonable certainty that the treated animal will not be consumed by humans or food-producing animals.

Dosage and Administration

Total doses used in captive minor species hoof stock to date have ranged from 1 mg (Impala) to 15 mg (African elephant). Immobilization is usually achieved in 2 to 10 minutes following administration. The most effective dose rate will vary due to the conditions of use. The lower end of the dose range is suggested for those animals of quiet temperament, under confinement, that have not been hotly pursued prior to administration of the drug, or for animals in poor physical condition. The upper end of the dose range is suggested for animals of excitable temperament following extensive pursuit or in instances where an extremely short chase time is desirable. The upper end of the dose range may also be appropriate for animals being pursued by vehicle or aircraft when an extremely quick immobilization time is desired or when individuals are known to be highly excitable. In all instances, all factors including nutritional, reproductive, and health status of an animals as well as environmental conditions (temperature, cover, and terrain) must be evaluated by the used and the best professional judgement used. DOSE CHART The following doses are representative of doses used in field trials. 1 Janssen, DL, GE Swan, JP Raath, SW McJames, JL Allen, V de Vos, KE Williams, JM Anderson, and TH Stanley. 1993. Immobilization and physiologic effects of narcotic A-3080 in impala (Aepyceros melampus). J. Zoo Wildl. Med., 24: 11-18. 2 Kreeger, TJ and JM Arnemo. 2007. Handbook of Wildlife Chemical Immobilization, 3rd ed. For North and South American orders: tkreeger@starband.net or Amazon.com. 3 Lance, WR. 2008 Attachemtn C; Recommended Dosages for Adult Animals South Africa and North America. Wildlife Pharmaceuticals, Inc, fort Collins, CO 80524. P. 9-10. 4 McJames, SW, IL Smith, TH Stanley, and G Painter. 1993. Elk immobilization with potent opioids: A3080 vs. carfentanil. Proc. Conf. Amer. Assoc. Zoo Vet., Saint Louis, Missouri. pp. 418-419. 5 Raath, JP. 2005. Clinical Expert Report First Study. pp. 1-11. 6 Raath, JP. 2005 Clinical Expert Report Second Study. pp. 11-22. 7 Stanley, TH, SW McJames, J Kimball, JD Port, and NL Pace. 1988. Immobilization of elk with A-3080. J. Wildl Mgmt. pp. 577-581. 8 Stanley, TH, SW McJames, and J Kimball. 1989. Chemical immobilization for the capture and transportation of big game. Proc. Conf. Amer. Assoc. Zoo Vet. Greensboro, North Carolina. pp. 13-14. Inject dose deep into a large muscle mass of the neck, shoulder, back, or hindquarter. Intra-thoracic, intra-abdominal, or subcutaneous injection is to be avoided. To ensure proper dosage for animals weighing less than 50 kg, remove the calculated dose of THIANIL from the vial with a tuberculin syringe. Dilute appropriate volume with sterile water for injection prior to administration. Operator should use safe technique by working in pairs, wearing disposable latex gloves, and wearing eye protection. Used syringes should be secured and disposed of in an appropriate biohazard container. Dose Chart ANTIDOTE: TREXONIL TM (naltrexone hydrochloride) is the recommended antidote and rapidly reverses the effects of THIANIL. Administer 10 mg TREXONIL TM for each milligram of THIANIL. The total calculated dose of TREXONIL TM should be administered intramuscular unless there is a medical or anesthetic emergency requiring immediate reversal, then ¼ of the calculated dose should be administered intravenously and ¾ of the calculated dose should be administered intramuscularly. The entire dose can be safely delivered intravenously but the operator should be prepared for occasional extrapyramidal activity and signs, and/or very rapid return to consciousness and mobility. Reversal of effects of THIANIL are usually observed in 2 to 10 minutes, with differences resulting from whether reversal is performed by intramuscular injection, split between intravenous injection and intramuscular injection, or completely delivered by intravenous injection.

Contraindications

THIANIL is not for use in minor species hoof stock in the family Equidae. Do not use thiafentanil oxalate in animals that display clinical signs of disease unless its use is imperative to establish a diagnosis and/or administer therapeutic agents. The effects of thiafentanil oxalate on reproductive performance, pregnancy, and lactation have not been determined. An opioid antagonist should always be drawn up, labelled, and readily accessible prior to drawing up thiafentanil oxalate.

Warnings

As with other opioids, all species immobilized with THIANIL may show signs of excitement, tachycardia or bradycardia, tachypnea or bradypnea, hypertension or hypotension, depressed respiration, cyanosis, poikilothermia, and reaction to sudden noise. Personnel should be advised of these potential opioid effects and trained to respond appropriately.

Precautions

THIAFENTANIL OXALATE SHOULD NEVER BE USED UNLESS AN ADEQUATE AMOUNT OF THE REVERSAL AGENT, TREXONIL TM (naltrexone hydrochloride), IS IMMEDIATELY AVAILABLE. Veterinarians using THIANIL should be familiar with clinical procedures such as measurement of pulse and respiration, oxygen saturation, prevention of aspiration, relief of bloat, obstetrics, control of shock and hemorrhage, recognition for hyperventilation, heat exhaustion, capture myopathy, and the immobilization of fractures, etc. In cases of severe excitement during induction or delayed recovery, continued observation is necessary to correct any of the above situations and to insure the animal does not injure itself.

Description

Thiafentanil oxalate is 4-(Methoxycarbonyl)-4- (N-phenylmethoxy-acetamido)-1-[2-(2-thienyl) ethyl] piperidinium oxalate. Its molecular formula is C 24 H 3 0N 2 O 2 S. Its molecular mass is 506.57. Each mL of THIANIL contains 10 mg thiafentanil oxalate and 0.1 % methylparaben. Structural Formula: Structural formula PHARMACOLOGY: Thiafentanil oxalate has a morphine-like analgesic mode of action and produces rapid immobilization following intramuscular injection.

Storage

Store at controlled room temperature (59-86 °F) in a facility consistent with appropriate Drug Enforcement Agency regulations regarding Schedule II N (narcotic) Class drugs. Protect from prolonged exposure to excessive heat.

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming thiafentanil as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.