Effect of reserpine or phenobarbitone on the acute toxicity of alphaxalone and alphadolone

Reserpine potentiated the acute toxicity of Althesin to a great extent. This was due to tranquilizing effect of reserpine, by depletion of catecholamines, and by release of progesterone which had considerable anaesthetic properties. Toxicity of thiopentone was less affected by reserpine. Phenobarbitone is a potent enzyme inducer. The rate of metabolism of Althesin was increased. So phenobarbitone antagonised the toxic effects of Althesin. Thiopentone was affected by phenobarbitone in the same way like althesin

Interaction of althesin and hypothermia

Althesin had hypotensive effect due to peripheral vasodilatation. Under hypothermia there are direct depression of the myocardium, of the pace maker, more liability for dysrythmias, decreased activity of the plasma protiens in binding Althesin, decreased rate of metabolism and reduction of plasma volume. Althesin may potentiate hypothermia by peripheral vasodilatation, skeletal muscle relaxation and antidysrythmic effect