formulary. Often injectable drugs are used in combinations . These drugs tend to have synergistic effects. Mixing them can significantly reduce the dosage needed for any individual drug. As with inhalation anesthesia, injectables are given to effect. Dosages listed are guidelines. Effects may vary among individuals. If a drug is scheduled by the Controlled Substances Act of 1970, licenses are required to purchase them, and written records must be kept of their use. University policy outlines these requirements.  Anesthetic drugs that have exceeded their expiration date may not be used , even for terminal procedures Injectable anesthetics are, in general, metabolized by the liver and excreted by the kidneys. Animals with liver or kidney disease should not be anesthetized with these agents. Inhalation anesthetics are safer for use in sick or debilitated animals, because there is minimal metabolism, the amount of anesthetic administered can be controlled and one can cease administration as the situation dictates. Injectable anesthetics offer the advantage of requiring less expensive equipment. Local Anesthetics The generic and brand names of local anesthetics often have the suffix " caine ". Common local anesthetics are procaine (Novacaine), bupivicaine, lidocaine (Xylocaine) and proparicaine. Considerable experience and skill are necessary in the administration of local anesthetics to animals, and aseptic techniques must be employed. Some animals must be sedated before local anesthetics are injected. Local anesthetics may be administered by several techniques. Anesthetic effects are seen within 15 minutes of administration and may last from 45 minutes to several hours, depending