Introduction

Company name: Merial Animal Health Ltd

Address: PO Box 327

Sandringham House

Harlow Business Park

Harlow

Essex CM19 5TG

Telephone: Companion Animals 0870 6000123

Production Animals 0800 592699

Fax: 01279 775888

Email: ukenquiry@merial.com

Website: www.merial.com

Presentation

A clear colourless volatile liquid for generation of gaseous anaesthetic, containing Halothane 100% w/w. Includes thymol 0.01% w/w as a preservative.

Uses

Induction and maintenance of general anaesthesia in horses, domestic animals, and non-domesticated mammals, birds and reptiles.

Dosage and administration

For administration by inhalation. HALOTHANE-VET may be administered using either open, semi-open or closed circuit systems. Closed circuit systems and endotracheal intubation should be used whenever possible.

Small animals

Induction: Anaesthesia is induced by using a concentration of Halothane in the range 2-4%. Alternatively a short acting induction agent (such as thiopentone sodium) may be used, and is to be preferred in large or excitable subjects.

Maintenance: Once a surgical plane of anaesthesia is reached, it may be maintained by a reduced concentration of between 0.5 and 2% depending on the size of the animal and the method used.

Horses not intended for human consumption

Induction: It may be possible to administer Halothane to a standing foal using a Cox mask but, as it is normally not practicable to induce anaesthesia in large animals using Halothane, induction should be by the use of a short acting intravenous agent such as thiopentone sodium. A concentration of 5-8% Halothane may then be used to complete the induction of surgical anaesthesia in 5-10 minutes.

Maintenance: Anaesthesia may be maintained by the administration of 0.8-2% Halothane vapour. Depending on the fresh gas flow-rate, to give this concentration to the animal it is usually necessary to deliver 1.5-5% from any out of circuit vaporiser, at least for the first hour.

Contra-indications, warnings, etc

For animal treatment only.

Halothane potentiates the action of non depolarising muscle relaxants such as gallamine and d-tubocurarine and dosage of these agents should be reduced.

Premedicants are frequently used to facilitate the induction of anaesthesia and reduce the required dosage of induction agents (such as short acting barbiturates) and inhalation agents. Particular care should be exercised in animals premedicated with alpha-2-adrenoceptor agonists.

During the induction of anaesthesia, a moderate fall in blood pressure commonly occurs. The pressure tends to rise when the vapour concentration is reduced to maintenance levels, but it usually remains steady below the pre-operative level.

Halothane causes dose-related respiratory and cardiovascular depression, and so respiration and pulse character should be monitored. Respiratory arrest should be treated by assisted ventilation with air, or preferably oxygen supplementation. It is important that a patent airway be maintained and adequate tissue oxygenation achieved throughout the period of anaesthesia. Should cardiac arrest occur, full cardiopulmonary resuscitation methods should be applied.

Halothane sensitises the heart to the catecholamines and the use of adrenaline should be avoided where possible.

Halothane delays involution of the uterus following caesarean section. Ecbolic drugs may need to be given to the mother after delivery of the offspring.

Malignant hyperthermia has been reported in the dog and horse but its incidence is rare.

Withdrawal period

Not to be used in animals intended for human consumption.

Treated horses may never be slaughtered for human consumption.

The horse must have been declared as not intended for human consumption under national Horse Passport legislation.

Operator Warnings

Do not breathe vapour.

Avoid contact by mouth.

Pregnant and breast-feeding women should avoid exposure to the product and should avoid operating rooms and animal recovery areas.

Use with efficient scavenging equipment. To protect the environment, the use of charcoal filters with such equipment is to be encouraged to reduce the amounts discharged to the atmosphere.

Ensure that the operating room has an adequate active extraction system. Care should be taken when dispensing Halothane, with any spillage removed immediately using inert and absorbent material e.g. sawdust.

Use cuffed endotrachael intubation whenever possible for the maintenance of general anaesthesia with Halothane.

Where possible, vaporisers should be filled outside the operating theatre or outdoors. Wash any splashes from skin and eyes immediately.

Avoid using masking procedures for prolonged induction and maintenance of general anaesthesia.

Induction/recovery areas should be well ventilated. All scavenging/extraction systems must be adequately maintained and anaesthetic equipment regularly checked for leaks.

Halothane can induce liver damage. This is an idiosyncratic response very occasionally seen after repeated exposure.

In the event of severe acute accidental exposure remove the operator from the source of exposure, seek urgent medical assistance and show this label.

Advice to doctors

Maintain a patent airway and give symptomatic and supportive treatment. Note that the use of adrenaline and catecholamines is contra-indicated since they may cause severe cardiac dysrhythmia.

Pharmaceutical precautions

Do not store above 25°C.

Protect from light.

Store in tightly closed original container.

Keep out of reach of children.

Legal category

POM-V

Packaging Quantities

Bottles of 250 ml.

Further information

Whilst in the liquid phase, HALOTHANE-VET must not be diluted or contaminated. However, in the vapour phase it may be administered together with oxygen or a mixture of nitrous oxide and oxygen.

Thymol 0.01% is included as a preservative according to BP requirement. As Halothane vaporises, the concentration of thymol increases and this can cause vaporiser controls to stick and ports to be occluded. Periodic servicing and recalibration of precision vaporisers is thus essential to ensure delivery of known concentration of Halothane vapour.

Dispose of any unused product and empty containers in accordance with guidance from your local waste regulation authority.

Marketing authorisation number

Vm 08327/4027.