Pharmacological Action

Thiafentanil oxalate is a pure opioid agonist that produces analgesia, immobilisation and profound anaesthesia in wildlife animals.

It is a synthetic analogue of fentanyl and has selective affinity for the µ-opioid receptors found throughout the central nervous system.

When thiafentanil is used alone in wildlife animals, the anaesthesia produced is characterised by extensive muscle rigidity, typical of opioid anaesthesia in most large ungulates.

Thiafentanil is fully reversed by naltrexone hydrochloride, which competitively binds to and displaces thiafentanil from the opioid receptors.

Pharmacokinetic and Pharmacodynamic Properties

Thiafentanil is lipid soluble and rapidly absorbed and metabolised following intramuscular injection.

It has a rapid onset of action and a relatively short duration of action.

Indications

THIANIL is indicated for reversible narcosis with analgesia in wildlife animals.

Contraindications

THIANIL is contraindicated in felid species and non-domestic equids, specifically Burchell’s zebra (Equus quagga burchellii).

Warnings

The safety of THIANIL during pregnancy and lactation has been proved in buffalo.

The safety of THIANIL in other pregnant and lactating wildlife animals has not been established. There is a risk of respiratory depression in the newborn animal if THIANIL is given to a parturient animal.

THIANIL residue studies have not been conducted in wildlife animals and consequently, carcasses from animals treated with THIANIL should not be used for human or predator consumption.

A withdrawal period of at least 3 months is required.

Dosage and Directions for Use

THIANIL dosing is dependent on species, body mass and the condition of the wildlife animal being treated.

Administration by intravenous or intramuscular injection is recommended. Refer to the recommended dosage table below.

The effects of THIANIL can be reversed by administering TREXONIL (naltrexone hydrochloride) at a ratio of 10 mg of TREXONIL for every 1 mg of THIANIL used.

Personnel should retreat sufficiently prior to reversal of THIANIL, as animals may rise in as little as 30 seconds after intravenous administration of TREXONIL.

Side Effects and Special Precautions for Use

Wildlife animals treated with THIANIL may show signs of excitement, tachycardia or tachypnoea, bradycardia or bradypnoea, hypertension or hypotension, cyanosis, poikilothermia and reaction to sudden noise.

Respiratory depression is particularly problematic in ungulate species immobilised with THIANIL. Possible increased appendicular and abdominal muscle rigidity may further hinder respiration.

Precautionary measures, including oxygen supplementation, should be taken to alleviate respiratory depression.

Precautionary steps must be taken to prevent the effects of extreme environmental temperatures on anaesthetised animals.

The use of THIANIL in elderly animals and animals with compromised health carries an additional degree of risk.

Accidental exposure to THIANIL could have serious effects on humans due to the high concentration of the medicine.

The following precautions should be taken by veterinarians when using THIANIL:

• Do not work with THIANIL when unaccompanied.
• Wear gloves when handling THIANIL. Ensure water or an appropriate irrigation solution is available to treat accidental exposure of the skin or eyes.
• Ensure that the antidote, naloxone, and a needle and syringe for administration of the antidote are readily available.
• An assistant capable of administering the antidote to humans should be present at all times and fully briefed on the procedure to follow in the event of accidental exposure.
• Once the required dose of THIANIL has been withdrawn from the vial, immediately discard the needle into a closed container or sharps bin.
• THIANIL should not be used in blowpipes or similar devices where the medicine solution is pressurised.
• Symptoms of toxicity in humans include dizziness, nausea, pinpoint pupils, cyanosis, respiratory depression, hypotension, loss of consciousness and cardiac arrest.
• In the event of accidental topical exposure of the skin or eyes, wash the affected area immediately with copious amounts of water to prevent absorption. Monitor for symptoms of toxicity.
• Should accidental injection occur, seek medical attention immediately. Inject the antidote intramuscularly or intravenously and repeat at 2–3 minute intervals until symptoms are reversed. Monitor airway and ventilation and initiate CPR as necessary until medical help arrives.

Known Symptoms of Overdosage and Particulars of Its Treatment

Symptoms of toxicity in wildlife animals include respiratory depression and/or severe cardiovascular changes.

Should respiratory function not recover sufficiently, TREXONIL or small increments of BUTADYNE 50 (butorphanol tartrate) can be administered.

Oxygen supplementation is recommended in the case of severe respiratory depression.

Identification

A clear, colourless solution free from visible particulate matter.

Presentation

THIANIL is supplied in a clear 10 ml vial with a grey rubber stopper and a white plastic cap.

Storage Instructions

Store at or below 25 °C.

Protect from light.

KEEP OUT OF REACH OF CHILDREN AND UNINFORMED PERSONS.

Registration Number

06/1.3/06

Holder of the Certificate of Registration

Wildlife Pharmaceuticals (Pty) Ltd
38 Wilken Street
Rocky Drift
White River
1240
South Africa

Date of Publication

22 September 2021

Recommended THIANIL Doses

Recommended THIANIL doses, alone or in combination with other medicines, based on literature and field efficacy data.

Dosage Table Notes

ɸ Higher dose range recommended for nervous or excited animals, or immobilisation where a short induction period is needed. Lower dose range recommended for weak, sick, debilitated or tame animals, where longer induction times are allowable, for animals in captivity, or where movement is restricted, for example in zoos.

¥ The level of opioid anaesthesia can be decreased to the desired level by concurrent IV administration of BUTADYNE 50.