Guaiacyl glyceryl ether (GGE), is a white, crystalline powder with a bitter taste. It is also known as guaifenesin and chemically as 3-(2-Methoxyphenoxy)-1, -2-propanediol. It is a central-acting skeletal muscle relaxant and is closely chemically related to mephenesin and meprobamate, other propanediol derivatives also widely used as muscle relaxants. GGE in addition has expectorant properties. It also increases the potency of pre-anaesthetic agents and barbiturates.
The propanediol derivatives selectively depress transmission of nerve impulses at the internuncial neurons of the spinal cord, brainstem and subtropical regions of the brain. Propanediol derivatives have a wide margin of safety, the toxic dose being three times greater than the recommended dose. Respiration is not severely depressed and the function of the diaphragm is uninterrupted. Tidal volume is slightly decreased and minute volume remains normal. In addition to skeletal muscle the pharyngeal and laryngeal muscles are sufficiently relaxed for easier surgical intubation procedures.
At the beginning of relaxation there is a slight fall in blood pressure. However, throughout the relaxation period the heart function is unchanged. There is a slight increase in astrointestinal activity. There is no apparent impairment of lung and kidney functions.
For equine use as a muscle relaxant, GGE Powder Kyron must be dissolved in water and then injected intravenously (see detailed instructions below).
At the recommended dosage, injection of GGE solution induction is usually smooth and rapid (2 to 4 minutes), providing a duration of action of between 15 and 25 minutes. Changes in heart rate, respiratory rate, right atrial pressure, pulmonary arterial pressure, and cardiac output are insignificant following administration in horses. A slightly transient haemolysis occurs at the recommended (5%) concentration, but higher concentrations will cause intravascular haemolysis. Accidental perivascular injection of the 5% solution does not result in severe tissue reaction.
DIRECTIONS FOR USE
Dissolve 50 grams in 1 litre of warm sterile water. This makes a 5% solution. Inject rapidly intravenously at the rate of 2ml/kg bodymass (100 mg per kg). Recumbency is normally attained in about 2 minutes, giving about 6 minutes of light, not quiet surgical level restraint. GGE is often used in combination with various other substances, e.g. xylazine, detomidine, thiopentone, ketamine, etc.
Store in a cool place away from light.
Reg. No. G1767 Act 36/1947