Mixtures of local anesthetics: bupivacaine-chloroprocaine.
Experiments were performed in a rat sciatic nerve preparation to determine the characteristics of nerve blocks produced by a combination of commercially available solutions of bupivacaine and chloroprocaine. A mixture of equal parts of commercially available chloroprocaine 2% and bupivacaine 0.5% resulted in a nerve blockade with characteristics of a chloroprocaine block. Changing the pH value of this mixture from 3.60 to 5.56 changed these characteristics to a blockade resembling that produced by bupivacaine. It is concluded that the nerve blockades obtained by mixing commercially available solutions of local anesthetics are unpredictable and may depend on a number of factors which include not only the types of drugs but the pH of the mixture.
D000200:Action Potentials / Q000187:drug effects; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage*; D004338:Drug Combinations; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D011343:Procaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D051381:Rats; D012584:Sciatic Nerve / Q000187:drug effects
D000779:Anesthetics, Local; D004338:Drug Combinations; D011343:Procaine; C004616:chloroprocaine; D002045:Bupivacaine