Methohexital Sodium

INDICATIONS AND USAGE Methohexital Sodium for Injection can be used in adults as follows: 1.For intravenous induction of anesthesia prior to the use of other general anesthetic agents. 2.For intravenous induction of anesthesia and as an adjunct to subpotent inhalational anesthetic agents (such as nitrous oxide in oxygen) for short surgical procedures; Methohexital Sodium for Injection may be given by infusion or intermittent injection. 3.For use along with other parenteral agents, usually narcotic analgesics, to supplement subpotent inhalational anesthetic agents (such as nitrous oxide in oxygen) for longer surgical procedures. 4.As intravenous anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli (see WARNINGS). 5.As an agent for inducing a hypnotic state. Methohexital Sodium for Injection can be used in pediatric patients older than 1 month as follows: 1.For rectal or intramuscular induction of anesthesia prior to the use of other general anesthetic agents. 2.For rectal or intramuscular induction of anesthesia and as an adjunct to subpotent inhalational anesthetic agents for short surgical procedures. 3.As rectal or intramuscular anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli.

DOSAGE AND ADMINISTRATION Facilities for assisting ventilation and administering oxygen are necessary adjuncts for all routes of administration of anesthesia. Since cardiorespiratory arrest may occur, patients should be observed carefully during and after use of Methohexital sodium for injection. Age- and size- appropriate resuscitative equipment (i.e., intubation and cardioversion equipment, oxygen, suction, and a secure intravenous line) and personnel qualified in its use must be immediately available. Preanesthetic medication is generally advisable. Methohexital Sodium for Injection may be used with any of the recognized preanesthetic medications. Preparation of Solution FOLLOW DILUTION INSTRUCTIONS EXACTLY. Freshly prepare solutions of Methohexital Sodium for Injection and use promptly. Reconstituted solutions of Methohexital Sodium for Injection are chemically stable at room temperature for 24 hours. Diluents ONLY USE BACTERIOSTATIC-FREE DILUENT - Recommended diluents are based on route of administration (See dilution instructions ). Incompatible diluents: Lactated Ringer's Injection Dilution Instructions 1% solutions (10 mg/mL) should be prepared for intermittent intravenous and rectal administration; 0.2% solutions (2 mg/mL) should be prepared for continuous intravenous drug administration; 5% solutions (50 mg/mL) should be prepared for intramuscular administration. Contents of vials should be diluted as follows: FOR INTERMITTENT INTRAVENOUS and RECTAL ADMINISTRATION The preferred diluent for intermittent intravenous and rectal administration is Sterile Water for Injection. 5% Dextrose Injection, or 0.9% Sodium Chloride Injection are also acceptable diluents. Strength Amount of Diluent to Be Added to the Contents of the Methohexital Sodium for Injection Vial For 1% methohexital solution (10 mg/mL) 500 mg 50 mL no further dilution needed FOR CONTINUOUS INTRAVENOUS ADMINISTRATION For continuous drip anesthesia, prepare a 0.2% solution by adding 500 mg of Methohexital Sodium for Injection to 250 mL of diluent. For this dilution, either 5% glucose solution or isotonic (0.9%) sodium chloride solution ONLY is recommended as the diluent instead of sterile water for injection in order to avoid extreme hypotonicity. Strength Amount of Diluent to Be Added to the Contents of the Methohexital Sodium for Injection Vial For 0.2% methohexital solution (2 mg/mL) 500 mg 15 mL add to 235 mL diluent for 250 mL total volume FOR INTRAMUSCULAR ADMINISTRATION The preferred diluent for intramuscular administration is Sterile Water for Injection. 0.9% Sodium Chloride Injection is also an acceptable diluent. Strength Amount of Diluent to Be Added to the Contents of the Methohexital Sodium for Injection Vial For 5% methohexital solution (50 mg/mL) 500 mg 10 mL no further dilution needed Administration Dosage is highly individualized; the drug should be administered only by those completely familiar with its quantitative differences from other barbiturate anesthetics. Adults Methohexital Sodium for Injection is administered intravenously in a concentration of no higher than 1 %. Higher concentrations markedly increase the incidence of muscular movements and irregularities in respiration and blood pressure. Induction of Anesthesia For induction of anesthesia, a 1% solution is administered at a rate of about 1 mL/5 seconds. Gaseous anesthetics and/or skeletal muscle relaxants may be administered concomitantly. The dose required for induction may range from 50 to 120 mg or more but averages about 70 mg. The usual dosage in adults ranges from 1 to 1.5 mg/kg. The induction dose usually provides anesthesia for 5 to 7 minutes Maintenance of anesthesia Maintenance of anesthesia may be accomplished by intermittent injections of the 1% solution or, more easily, by continuous intravenous drip of a 0.2% solution. Intermittent injections of about 20 to 40 mg (2 to 4 mL of a 1% solution) may be given as required, usually every 4 to 7 minutes. For continuous dri …

CONTRAINDICATIONS Methohexital Sodium for Injection is contraindicated in patients in whom general anesthesia is contraindicated, in those with latent or manifest porphyria, or in patients with a known hypersensitivity to barbiturates.

ADVERSE REACTIONS Side effects associated with Methohexital Sodium for Injection are extensions of pharmacologic effects and include: Cardiovascular Circulatory depression, thrombophlebitis, hypotension, tachycardia, peripheral vascular collapse, and convulsions in association with cardiorespiratory arrest Respiratory Respiratory depression (including apnea), cardiorespiratory arrest, laryngospasm, bronchospasm, hiccups, and dyspnea Neurologic Skeletal muscle hyperactivity (twitching), injury to nerves adjacent to injection site, and seizures Psychiatric Emergence delirium, restlessness, and anxiety may occur, especially in the presence of postoperative pain Gastrointestinal Nausea, emesis, abdominal pain, and liver function tests abnormal Allergic Erythema, pruritus, urticaria, and cases of anaphylaxis have been reported rarely Other Other adverse reactions include pain at injection site, salivation, headache, and rhinitis For medical advice about adverse reactions contact your medical professional. To report SUSPECTED ADVERSE REACTIONS, contact Avet Pharmaceuticals Inc. at 1-866-901-DRUG (3784) or FDA at 1-800-FDA-1088 or "http://www.fda.gov/medwatch".

DESCRIPTION Methohexital Sodium for injection, is 2,4,6 (1H, 3H, 5H)-Pyrimidinetrione, 1- methyl-5-(1-methyl-2-pentynyl)-5-(2-propenyl)-, (±)-, monosodium salt and has the empirical formula C 14 H 17 N 2 NaO 3 . Its molecular weight is 284.29. The structural formula is as follows: Methohexital sodium is a rapid, ultrashort-acting barbiturate anesthetic. Methohexital sodium for injection is a freeze-dried, sterile, nonpyrogenic mixture of methohexital sodium with 6% anhydrous sodium carbonate added as a buffer. It contains not less than 90% and not more than 110% of the labeled amount of methohexital sodium. It occurs as a white, freeze-dried plug that is freely soluble in water. This product is oxygen sensitive. The pH of the 1% solution is between 10 and 11; the pH of the 0.2% solution in 5% dextrose is between 9.5 and 10.5. Methohexital sodium may be administered by direct intravenous injection or continuous intravenous drip, intramuscular or rectal routes (See PRECAUTIONS/Pediatric Use ). Reconstituting instructions vary depending on the route of administration (See DOSAGE AND ADMINISTRATION ). structure

OVERDOSAGE Signs and Symptoms The onset of toxicity following an overdose of intravenously administered methohexital will be within seconds of the infusion. If methohexital is administered rectally or is ingested, the onset of toxicity may be delayed. The manifestations of an ultrashort-acting barbiturate in overdose include central nervous system depression, respiratory depression, hypotension, loss of peripheral vascular resistance, and muscular hyperactivity ranging from twitching to convulsive-like movements. Other findings may include convulsions and allergic reactions. Following massive exposure to any barbiturate, pulmonary edema, circulatory collapse with loss of peripheral vascular tone, and cardiac arrest may occur. Treatment To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison Control Center. Telephone numbers of certified poison control centers are listed in the Physicians’ Desk Reference (PDR). In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in your patient. Establish an airway and ensure oxygenation and ventilation. Resuscitative measures should be initiated promptly. For hypotension, intravenous fluids should be administered and the patient’s legs raised. If desirable increase in blood pressure is not obtained, vasopressor and/or inotropic drugs may be used as dictated by the clinical situation. For convulsions, diazepam intravenously and phenytoin may be required. If the seizures are refractory to diazepam and phenytoin, general anesthesia and paralysis with a neuromuscular blocking agent may be necessary. Protect the patient’s airway and support ventilation and perfusion. Meticulously monitor and maintain, within acceptable limits, the patient’s vital signs, blood gases, serum electrolytes, etc. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which, in many cases, is more effective than emesis or lavage; consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient’s airway when employing gastric emptying or charcoal.

HOW SUPPLIED Store between 20° to 25°C (68° to 77°F). (See USP Controlled Room Temperature.) Methohexital Sodium for Injection is a white, freeze-dried plug/lyophilized cake, filled in Vials*: The 500 mg vials (with 30 mg anhydrous sodium carbonate) are available as follows: • NDC 83270-003-01– Multi-Dose Vial – Pack of 1 *In crystalline form.