Comparative local anaesthetic activity of lignocaine, lignocaine-adrenaline and water extracts of Annona muricata during castration in dogs

Lignocaine is a local anaesthetic used in castration of dogs. However, lignocaine is sometimes combined with adrenaline in order to prolong the anaesthetic effect. Either lignocaine or lignocaine-adrenaline combination is associated with toxicity effects. Hence, anaesthetic potentials of lignocaine, lignocaine-adrenaline, fruit and stem-bark aqueous extract of Annona muricata were comparatively studied during castration in Nigerian indigenous dogs. Twelve adult dogs of about 1.00 ± 0.00-year-old and weighing 8.8 ± 0.4 kg divided into four groups of three each were used. The four groups were administered 2% lignocaine, lignocaine-adrenaline, fruit and stem-bark aqueous extracts each, at a dose of, 7.5 mg/kg each, by infiltration on the scrotal sac. After loss of sensation, ochidectomy was carried out. Time of onset and duration of anaesthesia were significantly higher (p < 0.05) in stem bark and fruit extract groups as compared to lignocaine and lignocaine-adrenaline groups. More so duration of anaesthesia was higher in lignocaine-adrenaline as compared to adrenaline. The findings have shown that lignocaine and lignocaine-adrenaline could increase whereas stem bark and fruit extract could decrease respiratory rate, respectively. Highest duration of anaesthesia was observed in stem- bark extract anaesthetized dogs followed by fruit extract treated group in comparison with lignocaine-adrenaline and lignocaine treated groups. Time of onset of anaesthesia was longest in fruit extract treated group and shortest in lignocaine and lignocaine-adrenaline treated groups respectively. Lignocaine and lignocaine/adrenaline increased and decreased haematological parameters, respectively. Lignocaine, lignocaine-adrenaline and the extracts altered biochemical parameters. Hence, Annona muricata could serve as potent local anaesthetic agent.