Levorphanol Tartrate

Levorphanol Tartrate Tablets are indicated for the management of pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate. Limitations of Use : Because of the risks of addiction, abuse, misuse, overdose, and death, which can occur at any dosage or duration and persist over the course of therapy ( see WARNINGS ), reserve opioid analgesics, including Levorphanol Tartrate Tablets for use in patients for whom alternative treatment options are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.

Levorphanol Tartrate Tablets are contraindicated in patients with: Significant respiratory depression ( see WARNINGS ) Acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment ( see WARNINGS ) Known or suspected gastrointestinal obstruction, including paralytic ileus ( see WARNINGS ) Hypersensitivity to levorphanol or any of the formulation excipients (e.g., anaphylaxis) ( see WARNINGS ).

Addiction, Abuse, and Misuse Levorphanol Tartrate Tablets contain levorphanol, a Schedule II controlled substance. As an opioid, Levorphanol Tartrate Tablets expose users to the risks of addiction, abuse, and misuse ( see DRUG ABUSE AND DEPENDENCE ). Although the risk of addiction in any individual is unknown, it can occur in patients appropriately prescribed Levorphanol Tartrate Tablets. Addiction can occur at recommended dosages and if the drug is misused or abused. The risk of opioid-related overdose or overdose-related death is increased with higher opioid doses, and this risk persists over the course of therapy. In postmarketing studies, addiction, abuse, misuse, and fatal and non-fatal opioid overdose were observed in patients with long-term opioid use ( see ADVERSE REACTIONS, Postmarketing Experience ). Assess each patient’s risk for opioid addiction, abuse, or misuse prior to prescribing Levorphanol Tartrate Tablets, and reassess all patients receiving Levorphanol Tartrate Tablets for the development of these behaviors and conditions. Risks are increased in patients with a personal or family history of substance abuse (including drug or alcohol abuse or addiction) or mental illness (e.g., major depression). The potential for these risks should not, however, prevent the proper management of pain in any given patient. Patients at increased risk may be prescribed opioids such as Levorphanol Tartrate Tablets, but use in such patients necessitates intensive counseling about the risks and proper use of Levorphanol Tartrate Tablets along with frequent reevaluation for signs of addiction, abuse and misuse. Consider recommending or prescribing an opioid overdose reversal agent ( see WARNINGS , DOSAGE AND ADMINISTRATION ). Opioids are sought for nonmedical use and are subject to diversion from legitimate prescribed use. Consider these risks when prescribing or dispensing Levorphanol Tartrate Tablets. Strategies to reduce these risks include prescribing the drug in smallest appropriate quantity and advising the patient on careful storage of the drug during the course of treatment and proper disposal of unused drug. Contact local state professional licensing board or state-controlled substances authority for information on how to prevent and detect abuse or diversion of this product. Life-Threatening Respiratory Depression Serious, life-threatening, or fatal respiratory depression has been reported with the use of opioids even when used as recommended. Respiratory depression, if not immediately recognized and treated, may lead to respiratory arrest and death. Management of respiratory depression may include close observation, supportive measures, and use of opioid overdose reversal agents, depending on the patient’s clinical status ( see OVERDOSAGE ). Carbon dioxide (CO 2 ) retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids. While serious, life-threatening, or fatal respiratory depression can occur at any time during the use of Levorphanol Tartrate Tablets, the risk is greatest during the initiation of therapy or following a dosage increase. To reduce the risk of respiratory depression, proper dosing and titration of Levorphanol Tartrate Tablets are essential ( see DOSAGE AND ADMINISTRATION ). Overestimating the Levorphanol Tartrate Tablets dosage when converting patients from another opioid product can result in a fatal overdose with the first dose. Accidental ingestion of even one dose of Levorphanol Tartrate Tablets, especially by children, can result in respiratory depression and death due to an overdose of Levorphanol Tartrate Tablets. Educate patients and caregivers on how to recognize respiratory depression and emphasize the importance of calling 911 or getting emergency medical help right away in the event of a known or suspected overdose ( see PRECAUTIONS, Information for Patients ). The initial dose of Levorphanol Tartrate Tablets should be reduced by 50% or more when the drug is given to patients with any condition affecting respiratory reserve or in conjunction with other drugs affecting the respiratory center. Subsequent doses should then be individually titrated according to the patient’s response. Opioids can cause sleep-related breathing disorders including central sleep apnea (CSA) and sleep-related hypoxemia. Opioid use increases the risk of CSA in a dose-dependent fashion. In patients who present with CSA, consider decreasing the opioid dosage using best practices for opioid taper ( see DOSAGE AND ADMINISTRATION ). Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose Inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene). Discuss the importance of having access to an opioid overdose reversal agent, especially if the patient has risk factors for overdose (e.g., concomitant use of CNS depressants, a history of opioid use disorder, or prior opioid overdose) or if there are household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose. The presence of risk factors for overdose should not prevent the management of pain in any patient ( see WARNINGS ). Discuss the options for obtaining an opioid overdose reversal agent (e.g., prescription, over-the-counter, or as part of a community-based program). There are important differences among the opioid overdose reversal agents, such as route of administration, product strength, approved patient age range, and pharmacokinetics. Be familiar with these differences, as outlined in the approved labeling for those products, prior to recommending or prescribing such an agent. Educate patients and caregivers on how to recognize respiratory depression, and how to use an opioid overdose reversal agent for the emergency treatment of opioid overdose. Emphasize the importance of calling 911 or getting emergency medical help, even if an opioid overdose reversal agent is administered ( see WARNINGS , OVERDOSAGE ). Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants Profound sedation, respiratory depression, coma, and death may result from the concomitant use of Levorphanol Tartrate Tablets with benzodiazepines and/or other CNS depressants, including alcohol [e.g., non-benzodiazepine sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), other opioids]. Because of these risks, reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to use of opioid analgesics alone. Because of similar pharmacological properties, it is reasonable to expect similar risk with the concomitant use of other CNS depressant drugs with opioid analgesics ( see PRECAUTIONS, Drug Interactions ). If the decision is made to prescribe a benzodiazepine or other CNS depressant concomitantly with an opioid analgesic, prescribe the lowest effective dosages and minimum durations of concomitant use. In patients already receiving an opioid analgesic, prescribe a lower initial dose of the benzodiazepine or other CNS depressant than indicated in the absence of an opioid, and titrate based on clinical response. If an opioid analgesic is initiated in a patient already taking a benzodiazepine or other CNS depressant, prescribe a lower initial dose of the opioid analgesic, and titrate based on clinical response. Inform patients and caregivers of this potential interaction, educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider recommending or prescribing an opioid overdose reversal agent ( see WARNINGS , DOSAGE AND ADMINISTRATION ). […]

Information for Patients Storage and Disposal Because of the risks associated with accidental ingestion, misuse, and abuse, advise patients to store Levorphanol Tartrate Tablets securely, out of sight and reach of children, and in a location not accessible by others, including visitors to the home. Inform patients that leaving Levorphanol Tartrate Tablets unsecured can pose a deadly risk to others in the home ( see WARNINGS , DRUG ABUSE AND DEPENDENCE ). Advise patients and caregivers that when medicines are no longer needed, they should be disposed of promptly. Expired, unwanted, or unused Levorphanol Tartrate Tablets should be disposed of by flushing the unused medication down the toilet if a drug take-back option is not readily available. Inform patients that they can visit www.fda.gov/drugdisposal for a complete list of medicines recommended for disposal by flushing, as well as additional information on disposal of unused medicines. Advise the patient to read the FDA-approved patient labeling (Medication Guide). Addiction, Abuse, and Misuse Inform patients that the use of Levorphanol Tartrate Tablets even when taken as recommended, can result in addiction, abuse, and misuse, which can lead to overdose and death ( see WARNINGS ). Instruct patients not to share Levorphanol Tartrate Tablets with others and to take steps to protect Levorphanol Tartrate Tablets from theft or misuse. Life-Threatening Respiratory Depression Inform patients of the risk of life-threatening respiratory depression, including information that the risk is greatest when starting Levorphanol Tartrate Tablets or when the dosage is increased, and that it can occur even at recommended dosages. Educate patients and caregivers on how to recognize respiratory depression and emphasize the importance of calling 911 or getting emergency medical help right away in the event of a known or suspected overdose ( see WARNINGS, Life-Threatening Respiratory Depression ). Accidental Ingestion Inform patients that accidental ingestion, especially by children, may result in respiratory depression or death ( see WARNINGS ). Interactions with Benzodiazepine and Other CNS Depressants Inform patients and caregivers that potentially fatal additive effects may occur if Levorphanol Tartrate Tablets are used with benzodiazepine or other CNS depressants, including alcohol [e.g., non-benzodiazepine sedative/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), and other opioids], and not to use these drugs concomitantly unless supervised by a healthcare provider ( see WARNINGS , PRECAUTIONS, Drug Interactions ). Patient Access to an Opioid Overdose Reversal Agent for the Emergency Treatment of Opioid Overdose Inform patients and caregivers about opioid overdose reversal agents (e.g., naloxone, nalmefene). Discuss the importance of having access to an opioid overdose reversal agent, especially if the patient has risk factors for overdose (e.g., concomitant use of CNS depressants, a history of opioid use disorder, or prior opioid overdose) or if there are household members (including children) or other close contacts at risk for accidental ingestion or opioid overdose. Discuss with the patient the options for obtaining an opioid overdose reversal agent (e.g., prescription, over-the-counter, or as part of a community-based program) ( see WARNINGS , DOSAGE AND ADMINISTRATION ). Educate patients and caregivers on how to recognize the signs and symptoms of an overdose. Explain to patients and caregivers that effects of opioid overdose reversal agents like naloxone and nalmefene are temporary, and that they must call 911 or get emergency medical help right away in all cases of known or suspected opioid overdose, even if an opioid overdose reversal agent is administered ( see OVERDOSAGE ). Advise patients and caregivers: how to treat with the overdose reversal agent in the event of an opioid overdose to tell family and friends about their opioid overdose reversal agent and to keep it in a place where family and friends can access it in an emergency to read the Patient Information (or other educational material) that will come with their opioid overdose reversal agent. Emphasize the importance of doing this before an opioid emergency happens, so the patient and caregiver will know what to do. Hyperalgesia and Allodynia Inform patients and caregivers not to increase opioid dosage without first consulting a clinician. Advise patients to seek medical attention if they experience symptoms of hyperalgesia, including worsening pain, increased sensitivity to pain, or new pain ( see WARNINGS , ADVERSE REACTIONS ). Serotonin Syndrome Inform patients that opioids could cause a rare but potentially life-threatening condition resulting from concomitant administration of serotonergic drugs. Warn patients of the symptoms of serotonin syndrome and to seek medical attention right away if symptoms develop. Instruct patients to inform their physician or healthcare provider if they are taking, or plan to take serotonergic medications ( see PRECAUTIONS, Drug Interactions ). Important Discontinuation Instructions In order to avoid developing withdrawal symptoms, instruct patients not to discontinue Levorphanol Tartrate Tablets without first discussing a tapering plan with the prescriber ( see DOSAGE AND ADMINISTRATION ). Driving or Operating Heavy Machinery Inform patients that Levorphanol Tartrate Tablets may impair the ability to perform potentially hazardous activities such as driving a car or operating heavy machinery. Advise patients not to perform such tasks until they know how they will react to the medication ( see PRECAUTIONS ). Constipation Advise patients of the potential for severe constipation, including management instructions and when to seek medical attention ( see ADVERSE REACTIONS ). Adrenal Insufficiency Inform patients that opioids could cause adrenal insufficiency, a potentially life-threatening condition. Adrenal insufficiency may present with non-specific symptoms and signs such as nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure. Advise patients to seek medical attention if they experience a constellation of these symptoms ( see WARNINGS ). Hypotension Inform patients that Levorphanol Tartrate Tablets may cause orthostatic hypotension and syncope. Instruct patients how to recognize symptoms of low blood pressure and how to reduce the risk of serious consequences should hypotension occur (e.g., sit or lie down, carefully rise from a sitting or lying position) ( see WARNINGS ). Anaphylaxis Inform patients that anaphylaxis has been reported with ingredients contained in Levorphanol Tartrate Tablets. Advise patients how to recognize such a reaction, and if they develop signs of allergy such as a rash or difficulty breathing to stop taking Levorphanol Tartrate Tablets and seek medical attention ( see CONTRAINDICATIONS , ADVERSE REACTIONS ). Pregnancy Neonatal Opioid Withdrawal Syndrome Inform female patients of reproductive potential that use of Levorphanol Tartrate Tablets for an extended period of time during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated ( see WARNINGS , PRECAUTIONS, Pregnancy ). Embryo-Fetal Toxicity Inform female patients of reproductive potential that Levorphanol Tartrate Tablets can cause fetal harm and to inform the prescriber of a known or suspected pregnancy ( see WARNINGS , PRECAUTIONS, Pregnancy ). Lactation Advise nursing mothers to carefully observe infants for increased sleepiness (more than usual), breathing difficulties, or limpness. Instruct nursing mothers to see immediate medical care if they notice these signs ( see PRECAUTIONS , Nursing Mothers ). Infertility Inform patients that use of opioids for an extended period of time may cause reduced fertility. […]

In approximately 1400 patients treated with Levorphanol Tartrate Tablets in controlled clinical trials, the type and incidence of side effects were those expected of an opioid analgesic, and no unforeseen or unusual toxicity was reported. Drugs of this type are expected to produce a cluster of typical opioid effects in addition to analgesia, consisting of nausea, vomiting, altered mood and mentation, pruritus, flushing, difficulties in urination, constipation, and biliary spasm. The frequency and intensity of these effects appears to be dose related. Although listed as adverse events these are expected pharmacologic actions of these drugs and should be interpreted as such by the clinician. The following adverse events have been reported with the use of Levorphanol Tartrate Tablets: Body as a Whole: abdominal pain, dry mouth, sweating Cardiovascular System: cardiac arrest, shock, hypotension, arrhythmias including bradycardia and tachycardia, palpitations, extra-systoles Digestive System: nausea, vomiting, dyspepsia, biliary tract spasm Nervous System: coma, suicide attempt, convulsions, depression, dizziness, confusion, lethargy, abnormal dreams, abnormal thinking, nervousness, drug withdrawal, hypokinesia, dyskinesia, hyperkinesia, CNS stimulation, personality disorder, amnesia, insomnia Respiratory System: apnea, cyanosis, hypoventilation Skin & Appendages: pruritus, urticaria, rash, injection site reaction Special Senses: abnormal vision, pupillary disorder, diplopia Urogenital System: kidney failure, urinary retention, difficulty urinating Postmarketing Experience The following adverse reactions have been identified during post-approval use of levorphanol. Because these reactions are 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. Serotonin syndrome: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs. Adrenal insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Anaphylaxis: Anaphylaxis has been reported with ingredients contained in Levorphanol Tartrate Tablets. Androgen deficiency: Cases of androgen deficiency have occurred with use of opioids for an extended period of time ( see CLINICAL PHARMACOLOGY ). Hyperalgesia and Allodynia: Cases of hyperalgesia and allodynia have been reported with opioid therapy of any duration ( see WARNINGS ). Hypoglycemia: Cases of hypoglycemia have been reported in patients taking opioids. Most reports were in patients with at least one predisposing risk factor (e.g., diabetes). Opioid-induced esophageal dysfunction (OIED): Cases of OIED have been reported in patients taking opioids and may occur more frequently in patients taking higher doses of opioids, and/or in patients taking opioids longer term ( see WARNINGS ). Adverse Reactions from Observational Studies A prospective, observational cohort study estimated the risks of addiction, abuse, and misuse in patients initiating long-term use of Schedule II opioid analgesics between 2017 and 2021. Study participants included in one or more analyses had been enrolled in selected insurance plans or health systems for at least one year, were free of at least one outcome at baseline, completed a minimum number of follow-up assessments, and either: 1) filled multiple extended-release/long-acting opioid analgesic prescriptions during a 90 day period (n=978); or 2) filled any Schedule II opioid analgesic prescriptions covering at least 70 of 90 days (n=1,244). Those included also had no dispensing of the qualifying opioids in the previous 6 months. Over 12 months: approximately 1% to 6% of participants across the two cohorts newly met criteria for addiction, as assessed with two validated interview-based measures of moderate-to-severe opioid use disorder based on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria, and approximately 9% and 22% of participants across the two cohorts newly met criteria for prescription opioid abuse and misuse [defined in DRUG ABUSE AND DEPENDENCE ] , respectively, as measured with a validated self-reported instrument. A retrospective, observational cohort study estimated the risk of opioid-involved overdose or opioid overdose-related death in patients with new long-term use of Schedule II opioid analgesics from 2006 through 2016 (n=220,249). Included patients had been enrolled in either one of two commercial insurance programs, one managed care program, or one Medicaid program for at least 9 months. New long-term use was defined as having Schedule II opioid analgesic prescriptions covering at least 70 days’ supply over the 3 months prior to study entry and none during the preceding 6 months. Patients were excluded if they had an opioid-involved overdose in the 9 months prior to study entry. Overdose was measured using a validated medical code-based algorithm with linkage to the National Death Index database. The 5-year cumulative incidence estimates for opioid-involved overdose or opioid overdose-related death ranged from approximately 1.5% to 4% across study sites, counting only the first event during follow-up. Approximately 17% of first opioid overdoses observed over the entire study period (5-11 years, depending on the study site) were fatal. Higher baseline opioid dose was the strongest and most consistent predictor of opioid-involved overdose or opioid overdose-related death. Study exclusion criteria may have selected patients at lower risk of overdose, and substantial loss to follow-up (approximately 80%) also may have biased estimates. The risk estimates from the studies described above may not be generalizable to all patients receiving opioid analgesics, such as those with exposures shorter or longer than the duration evaluated in the studies.

Benzodiazepines and Other Central Nervous System (CNS) Depressants Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, and other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, gabapentinoids (gabapentin or pregabalin), and other opioids, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Inform patients and caregivers of this potential interaction, educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider recommending or prescribing an opioid overdose reversal agent ( see WARNINGS , DOSAGE AND ADMINISTRATION ). Serotonergic Drugs The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system, such as selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), triptans, 5-HT3 receptor antagonists, drugs that affect the serotonin neurotransmitter system (e.g., mirtazapine, trazodone, tramadol), certain muscle relaxants (i.e., cyclobenzaprine, metaxalone), and monoamine oxidase (MAO) inhibitors (those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue), has resulted in serotonin syndrome ( see PRECAUTIONS, Information for Patients ). If concomitant use is warranted, frequently evaluate the patient, particularly during treatment initiation and dose adjustment. Discontinue Levorphanol Tartrate Tablets if serotonin syndrome is suspected. Mixed Agonist/Antagonist and Partial Opioid Analgesics The concomitant use of opioid with other opioid analgesics, such as butorphanol, nalbuphine, pentazocine, may reduce the analgesic effect of Levorphanol Tartrate Tablets and precipitate withdrawal symptoms. Advise patient to avoid concomitant use of these drugs. Muscle Relaxants Levorphanol may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. If concomitant use is warranted, because respiratory depression may be greater than otherwise expected, decrease the dosage of Levorphanol Tartrate Tablets and/or the muscle relaxant as necessary. Due to the risk of respiratory depression with concomitant use of skeletal muscle relaxants and opioids, consider recommending or prescribing an opioid overdose reversal agent ( see WARNINGS , DOSAGE AND ADMINISTRATION ). Examples: Cyclobenzaprine, metaxalone. Diuretics Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. If concomitant use is warranted, evaluate patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed. Anticholinergic Drugs The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. If concomitant use is warranted, evaluate patients for signs of urinary retention or reduced gastric motility when Levorphanol Tartrate Tablets are used concomitantly with anticholinergic drugs.

Risk Summary Use of opioid analgesics for an extended period of time during pregnancy may cause neonatal opioid withdrawal syndrome ( see WARNINGS ). Available data with Levorphanol Tartrate Tablets in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, oral levorphanol produced malformations and nearly 50% embryo lethality in mice at 10 and 12 times the human daily dose of 12 mg/day, respectively. Paternal exposure to levorphanol prior to mating to an untreated female resulted in reduced litter birth weights, developmental delays, and aberrant behavior in a swim maze at 34 times the human daily dose of 12 mg/day. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Use of opioid analgesics for an extended period of time during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly ( see WARNINGS ). Labor or Delivery Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates. An opioid overdose reversal agent, such as naloxone or nalmefene, must be available for reversal of opioid-induced respiratory depression in the neonate. Levorphanol Tartrate Tablets are not recommended for use in pregnant women during or immediately prior to labor, when other analgesic techniques are more appropriate. Opioid analgesics, including Levorphanol Tartrate Tablets can prolong labor through actions which temporarily reduce the strength, duration, and frequency of uterine contractions. However, this effect is not consistent and may be offset by an increased rate of cervical dilation, which tends to shorten labor. Monitor neonates exposed to opioid analgesics during labor for signs of excess sedation and respiratory depression. Animal Data In a published study, levorphanol has been shown to cause central nervous system malformations consistent with neural tube defects (kinking of the spinal cord, hydromyelia, dilation of the fourth ventricle, and brachyury) in pregnant mice when given a single subcutaneous dose of 25 mg/kg (10 times the human daily dose of 12 mg/day based on a body surface area comparison) on Gestation Day 9. Subcutaneous administration of 30 mg/kg levorphanol to pregnant mice on Gestation Day 9 resulted in approximately 50% mortality of the mouse embryos (12 times the human daily dose of 12 mg/day). In another published study, male mice were injected subcutaneously twice daily with increasing daily doses of levorphanol up to 42 mg/kg/day (34 times the human daily dose of 12 mg based on body surface area) for 5.5 to 8.5 days prior to mating with an untreated female. Paternal exposure to levorphanol resulted in reduced birth weights of the litters, developmental delays in the offspring, and aberrant swim patterns in the progeny when measured at 6.5 to 8.5 weeks of age.

Risk Summary The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Levorphanol Tartrate Tablets and any potential adverse effects on the breastfed infant from Levorphanol Tartrate Tablets or from the underlying maternal condition. Clinical Considerations Infants exposed to Levorphanol Tartrate Tablets through breast milk should be monitored for excess sedation and respiratory depression. Withdrawal symptoms can occur in breastfed infants when maternal administration of an opioid analgesic is stopped, or when breastfeeding is stopped. Data Studies of levorphanol concentrations in breast milk have not been performed. However, morphine, which is structurally similar to levorphanol, is excreted in human milk. Because of the potential for serious adverse reactions from levorphanol in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Levorphanol Tartrate Tablets are not recommended in children under the age of 18 years as the safety and efficacy of the drug in this population has not been established.

Elderly patients (aged 65 years or older) may have increased sensitivity to levorphanol. In general, use caution when selecting a dosage for an elderly patient, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy. The initial dose of Levorphanol Tartrate Tablets should be reduced by 50% or more in the infirm elderly patient. Respiratory depression is the chief risk for elderly patients treated with opioids, and has occurred after large initial doses were administered to patients who were not opioid- tolerant or when opioids were co-administered with other agents that depress respiration. Titrate the dosage of Levorphanol Tartrate Tablets slowly in geriatric patients and frequently reevaluate the patient for signs of central nervous system and respiratory depression ( see WARNINGS ). This drug is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to regularly evaluate renal function.

Levorphanol is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of levorphanol is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with levorphanol. Clinically, dosage is titrated to provide adequate analgesia and may be limited by adverse reactions, including respiratory and CNS depression. The precise mechanism of the analgesic action is unknown. However, specific CNS opioid receptors for endogenous compounds with opioid-like activity have been identified throughout the brain and spinal cord and are thought to play a role in the analgesic effects of this drug.