Ketamine

12.1 Mechanism of Action KETALAR, a racemic mixture of ketamine, is a non-selective, non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, an ionotropic glutamate receptor. The major circulating metabolite of ketamine (norketamine) demonstrated activity at the same receptor with less affinity. Norketamine is about 1/3 as active as ketamine in reducing halothane requirements (MAC) of the rat.

1 INDICATIONS AND USAGE KETALAR (ketamine hydrochloride) injection is indicated: as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation. for the induction of anesthesia prior to the administration of other general anesthetic agents. as a supplement to other anesthetic agents. KETALAR is a general anesthetic indicated: as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation ( 1 ) for the induction of anesthesia prior to the administration of other general anesthetic agents ( 1 ) as a supplement to other anesthetic agents ( 1 ).

2 DOSAGE AND ADMINISTRATION See Full Prescribing Information for important dosage and administration instructions. ( 2 ) Induction of anesthesia: -- Intravenous route : Initially, 1 to 4.5 mg/kg administered slowly (over a period of 60 seconds). Alternatively, administer a dose of 1 to 2 mg/kg at a rate of 0.5 mg/kg/min. ( 2.2 ) -- Intramuscular route : Initially, 6.5 to 13 mg/kg. ( 2.2 ) Maintenance of anesthesia: Increments of one-half to the full induction dose may be repeated as needed ( 2.2 ). Adjust the dose according to the patient's anesthetic needs and whether an additional anesthetic agent is employed. ( 2.2 ) Supplement to other anesthetic agents : The regimen of a reduced dose of KETALAR supplemented with diazepam can be used to produce balanced anesthesia by combination with other agents. ( 2.2 ) 2.1 Important Dosage and Administration Information KETALAR should be administered by or under the direction of physicians experienced in the administration of general anesthetics, maintenance of a patent airway, and oxygenation and ventilation. Continuously monitor vital signs in patients receiving KETALAR. Emergency airway equipment must be immediately available. Do not administer the 100 mg/mL concentration of KETALAR intravenously without proper dilution [see Dosage and Administration ( 2.3 )] . Must be used immediately after dilution. While some degree of airway protection may be afforded due to active laryngeal-pharyngeal reflexes, vomiting and aspiration may occur with KETALAR. KETALAR is not recommended for use in patients who have not followed nil per os guidelines. Due to the potential for salivation during KETALAR administration, administer an antisialagogue prior to induction of anesthesia. In individuals with a history of chronic ketamine use for off-label indications, there have been case reports of genitourinary pain that may be related to the ketamine treatment, not the underlying condition [see Adverse Reactions ( 6 )] . Consider cessation of ketamine if genitourinary pain continues in the setting of other genitourinary symptoms. 2.2 Recommended Dosage and Administration The KETALAR dosage must be individualized and titrated to the desired clinical effect. If a longer duration of effect is desired, additional increments can be administered intravenously or intramuscularly to maintain anesthesia. However, a higher total dose will result in a longer time to complete recovery. Induction of Anesthesia Intravenous Route: The initial dose of KETALAR administered intravenously may range from 1 mg/kg to 4.5 mg/kg. The average amount required to produce 5 to 10 minutes of surgical anesthesia within 30 seconds following injection is 2 mg/kg. Administer KETALAR slowly (i.e., over a period of 60 seconds). Rapid administration may result in respiratory depression and enhanced vasopressor response. The induction dose may be administered as an intravenous infusion at a rate of 0.5 mg/kg/min. Intramuscular Route : The initial dose of KETALAR administered intramuscularly may range from 6.5 to 13 mg/kg. A dose of 9 to 13 mg/kg usually produces surgical anesthesia within 3 to 4 minutes following injection, with the anesthetic effect usually lasting 12 to 25 minutes. Administer a benzodiazepine, if clinically indicated, for the prevention of neuropsychological manifestations during emergence from anesthesia. Maintenance of Anesthesia Adjust the maintenance dose according to the patient's anesthetic needs and whether an additional anesthetic agent is administered. Repeat increments of one-half to the full induction dose as needed for maintenance of anesthesia. Purposeless and tonic-clonic movements of extremities may occur during the course of ketamine anesthesia. These movements do not imply a light plane and are not indicative of the need for additional doses of the anesthetic. KETALAR given by slow microdrip infusion technique at a dose of 0.1 to 0.5 mg/minute will maintain general anesthesia in adult patients induced with KETALAR. Augment KETALAR with an intravenous benzodiazepine for the prevention of neuropsychological manifestations during emergence. Supplement to Other Anesthetic Agents KETALAR can be administered to supplement other general and local anesthetic agents. Continuously monitor patients for changes in respiratory and hemodynamic parameters. A reduced dose of KETALAR can be used to produce balanced anesthesia when used in combination with other anesthetic agents. 2.3 Preparation of Dilution KETALAR is a clear, colorless sterile solution. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard if product is discolored or contains particulate matter. Induction of Anesthesia : Do not intravenously inject the 100 mg/mL concentration of KETALAR without proper dilution. Dilute KETALAR with an equal volume of either Sterile Water for injection, USP, 0.9% Sodium Chloride Injection, US

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Hemodynamic Instability [see Warnings and Precautions ( 5.1 )] Emergence Reactions [see Warnings and Precautions ( 5.2 )] Respiratory Depression [see Warnings and Precautions ( 5.3 )] Pediatric Neurotoxicity [see Warnings and Precautions ( 5.5 )] Drug-Induced Liver Injury [see Warnings and Precautions ( 5.6 )] The following adverse reactions associated with the use of KETALAR were identified in clinical studies or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular disorders : Elevated blood pressure, heart rate, and cardiac index; decreases in blood pressure and heart rate; arrhythmias; cardiac decompensation (in patients with suspected catecholamine depletion). Eye disorders : Diplopia, nystagmus, elevation in intraocular pressure. Gastrointestinal disorders : Anorexia, nausea, vomiting, hepatobiliary dysfunction. Biliary duct dilatation and/or biliary duct stricture and/or stenosis with or without evidence of biliary obstruction and secondary sclerosing cholangitis has been reported with recurrent use (e.g., misuse/abuse or medically supervised unapproved indications). Administration site disorders : Local pain and exanthema at the injection site. Immune system disorders : Anaphylaxis. Neurologic disorders : Emergence reactions (post-operative delirium), [see Warnings and Precautions ( 5.2 )]. During administration, enhanced muscle tone and spasms (resembling a partial motor or generalized motor seizure). Psychiatric disorders : Adverse psychiatric events have occurred and/or persisted days to weeks after ketamine exposure. Renal and urinary disorders: In individuals with history of chronic ketamine use or abuse, lower urinary tract and bladder symptoms including dysuria, increased urinary frequency, urgency, urge incontinence, and hematuria have been reported [see Dosage and Administration ( 2.1 )] . In addition, diagnostic studies performed to assess the cause of these symptoms have reported cystitis (including cystitis non-infective, cystitis interstitial, cystitis ulcerative, cystitis erosive and cystitis hemorrhagic), ureteric stenosis (strictures), ureteric obstruction as well as hydronephrosis and reduced bladder capacity. Respiratory disorders : Respiratory depression and apnea following rapid intravenous administration of high doses of KETALAR; laryngospasm, and airway obstruction. Skin and subcutaneous tissue disorders : Transient erythema and/or morbilliform rash The most common adverse reactions are emergence reactions and elevated blood pressure and pulse ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Par Health at 1-800-828-9393 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

7 DRUG INTERACTIONS Theophylline or Aminophylline : Do not co-administer with KETALAR as concomitant use may lower the seizure threshold ( 7.1 ). Sympathomimetics and Vasopressin : Closely monitor vital signs when co-administered with KETALAR. Consider dose adjustment individualized to the patient’s clinical situation ( 7.2 ). Benzodiazepines, Opioid Analgesics, or other CNS Depressants : Concomitant use may result in profound sedation, respiratory depression, coma, or death. Concomitant use of opioid analgesics may prolong recovery time. ( 7.3 ). 7.1 Theophylline or Aminophylline Concomitant administration of KETALAR and theophylline or aminophylline may lower the seizure threshold. Consider using an alternative to KETALAR in patients receiving theophylline or aminophylline. 7.2 Sympathomimetics and Vasopressin Sympathomimetics and vasopressin may enhance the sympathomimetic effects of ketamine. Closely monitor vital signs when KETALAR and sympathomimetics or vasopressin are co-administered and consider dose adjustment individualized to the patient’s clinical situation. 7.3 Benzodiazepines, Opioid Analgesics, Or Other CNS Depressants Concomitant use of ketamine with opioid analgesics, benzodiazepines, or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death [see Warnings and Precautions ( 5.8 )] . Opioid analgesics administered concomitantly with KETALAR may prolong time to complete recovery from anesthesia.