Relative Toxicity ratios of bupvacaine and lignocaine AGENT CVS/CNS RATIO ANIMAL BUPIVACAINE 2.7 SHEEP (PREGNANT) 3.7 SHEEP (NON-PREGNANT) 4.5 DOGS (AWAKE) 4.8 CATS (VENTILATED) LIGNOCAINE 2.6 CATS (VENTILATED) 3.5 DOGS (AWAKE) 7.1 SHEEP (NON-PREGNANT)