Signs and Symptoms

All but a few cases of ORLAAM overdose have involved multiple drugs. Overdose on ORLAAM alone is rare and has always been the result of too frequent (daily) dosing. Overdose is primarily of concern in persons not tolerant to opiates, since in such individuals a dose of 20 to 40 mg of ORLAAM may cause somnolence, and a larger initial dose may cause serious overdose. Tolerant individuals will generally not show symptoms unless higher doses are administered.

In ORLAAM overdose, as with other mu agonist opioids, the following signs and symptoms should be anticipated: respiratory depression (decrease in respiratory rate and/or tidal volume, Cheyenne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, maximally constricted pupils, skeletal muscle flaccidity, cold and clammy skin, bradycardia, and hypotension. In severe overdose, apnea, circulatory collapse, pulmonary edema, cardiac arrest and death may occur.

Treatment

In the case of ORLAAM overdose, protect the patient's airway and support ventilation and circulation. Absorption of ORLAAM from the gastrointestinal tract may be decreased by gastric emptying and/or administration of activated charcoal. (Safeguard the patient's airway when employing gastric emptying or administering charcoal in any patient with diminished consciousness). Forced diuresis, peritoneal dialysis, hemodialysis, or charcoal hemoperfusion are unlikely to be beneficial for ORLAAM overdose due to its high lipid solubility and large volume of distribution.

In managing ORLAAM overdose, the physician should consider the possibility of multiple drugs, the interaction between drugs, and any unusual drug kinetics in the patient. Naloxone may be given to antagonize opiate effects, but the airway must be secured as vomiting may ensue. If possible, naloxone should be titrated to clinical effect rather than given as a large single bolus, since rapid reversal of opioid effects by large naloxone doses can cause severe precipitated withdrawal effects that may include cardiac instability. If a patient has received a total of 10 mg of naloxone without clinical response, the diagnosis of opioid overdose is unlikely.

If the patient does respond to naloxone, the physician should remember that the duration of ORLAAM activity is much longer (days) than that of naloxone (minutes) and repeated dosing with or continuous intravenous infusion of naloxone is likely to be required. Use of oral naltrexone in this setting is not recommended because it may precipitate prolonged opioid withdrawal symptoms (see Use of Narcotic Antagonists ).

ORLAAM is contraindicated in patients with known or suspected QT prolongation (QTc interval greater than 430 [male] or 450 [female] ms). This would include patients with congenital long QT syndrome, or conditions which may lead to QT prolongation (see WARNINGS, Effects on Cardiac Conduction ) such as: 1) clinically significant bradycardia (less than 50 bpm), 2) any clinically significant cardiac disease, 3) treatment with Class I and Class III anti-arrhythmics, 4) treatment with monoamine oxidase inhibitors (MAOI's), 5) concomitant treatment with other drug products known to prolong the QT interval (see PRECAUTIONS , Drug Interactions ), and 6) electrolyte imbalance, in particular hypokalemia and hypomagnesemia.

ORLAAM is contraindicated in patients with known hypersensitivity to LAAM.

ORLAAM is not recommended for any use other than for the treatment of opioid dependence (see WARNINGS ).

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