Tuxarin Prescribing Information

Important Limitations of Use

• Not indicated for pediatric patients under 18 years of age [see Use in Specific Population (8.4)].
• Contraindicated in pediatric patients under 12 years of age [see Contraindications (4), Use in Specific Populations (8.4)].
• Contraindicated in pediatric patients 12 to 18 years of age after tonsillectomy or adenoidectomy [see Contraindications (4), Use in Specific Populations (8.4)].
• Because of the risks of addiction, abuse, and misuse with opioids, even at recommended doses [see Warnings and Precautions (5.1)], reserve TUXARIN ER for use in adult patients for whom the benefits of cough suppression are expected to outweigh the risks, and in whom an adequate assessment of the etiology of the cough has been made.

2.1 Important Dosage and Administration Instructions

Administer TUXARIN ER by the oral route only.

Advise patients not to increase the dose or dosing frequency of TUXARIN ER because serious adverse events such as respiratory depression may occur with overdosage [see Warnings and Precautions (5.2), Overdosage (10)]. The dosage of TUXARIN ER should not be increased if cough fails to respond; an unresponsive cough should be reevaluated for possible underlying pathology [see Dosage and Administration (2.3), Warnings and Precautions (5.5)].

2.2 Recommended Dosage

2.3 Monitoring, Maintenance, and Discontinuation of Therapy

Prescribe TUXARIN ER for the shortest duration that is consistent with individual patient treatment goals [see Warnings and Precautions (5.1)]

Monitor patients closely for respiratory depression, especially within the first 24-72 hours of initiating therapy [see Warnings and Precautions (5.2)].

Reevaluate patients with unresponsive cough in 5 days or sooner for possible underlying pathology, such as foreign body or lower respiratory tract disease [see Warnings and Precautions (5.5)]. If a patient requires a refill, reevaluate the cause of the cough and assess the need for continued treatment with TUXARIN ER, the relative incidence of adverse reactions, and the development of addiction, abuse, or misuse [see Warnings and Precautions (5.1)].

Do not abruptly discontinue TUXARIN ER in a physically-dependent patient [see Drug Abuse and Dependence (9.3)]. When a patient who has been taking TUXARIN ER regularly and may be physically dependent no longer requires therapy with TUXARIN ER, taper the dose gradually, by 25% to 50% every 2 to 4 days, while monitoring carefully for signs and symptoms of withdrawal. If the patient develops these signs or symptoms, raise the dose to the previous level and taper more slowly, either by increasing the interval between decreases, decreasing the amount of change in dose, or both.

5.1 Addiction, Abuse, and Misuse

TUXARIN ER contains codeine, a Schedule III controlled substance. As an opioid, TUXARIN ER exposes users to the risks of addiction, abuse, and misuse [see Drug Abuse and Dependence (9)], which can lead to overdose and death [see Overdosage (10)]. Reserve TUXARIN ER for use in adult patients for whom the benefits of cough suppression are expected to outweigh the risks, and in whom an adequate assessment of the etiology of the cough has been made. Assess each patient's risk prior to prescribing TUXARIN ER, prescribe TUXARIN ER for the shortest duration that is consistent with individual patient treatment goals, monitor all patients regularly for the development of addiction or abuse, and refill only after reevaluation of the need for continued treatment.

Although the risk of addiction in any individual is unknown, it can occur in patients appropriately prescribed TUXARIN ER. Addiction can occur at recommended dosages and if the drug is misused or abused. 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).

Opioids are sought by drug abusers and people with addiction disorders and are subject to criminal diversion. Consider these risks when prescribing or dispensing TUXARIN ER. Strategies to reduce these risks include prescribing the drug in the smallest appropriate quantity and advising the patient on the proper disposal of unused drug [see Patient Counseling Information (17)]. 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.

5.2 Life-Threatening Respiratory Depression

Serious, life-threatening, or fatal respiratory depression has been reported with the use of opioids, including codeine, one of the active ingredients in TUXARIN ER. Codeine produces dose-related respiratory depression by directly acting on the brain stem respiratory center that controls respiratory rhythm and may produce irregular and periodic breathing. Codeine is subject to variability in metabolism based upon CYP2D6 genotype, which can lead to an increased exposure to the active metabolite morphine [see Warnings and Precautions (5.3)]. Respiratory depression, if not immediately recognized and treated, may lead to respiratory arrest and death. Management of respiratory depression includes discontinuation of TUXARIN ER, close observation, supportive measures, and use of opioid antagonists (e.g. naloxone), depending on the patient's clinical status [see Overdosage (10)]. Carbon dioxide (CO2) 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 TUXARIN ER, the risk is greatest during the initiation of therapy, when TUXARIN ER is used concomitantly with other drugs that may cause respiratory depression [see Warnings and Precautions (5.9)], in patients with chronic pulmonary disease or decreased respiratory reserve, and in patients with altered pharmacokinetics or altered clearance (e.g. elderly, cachectic, or debilitated patients) [see Warnings and Precautions (5.5)].

To reduce the risk of respiratory depression, proper dosing of TUXARIN ER is essential [see Dosage and Administration (2.1), Warnings and Precautions (5.6)]. Monitor patients closely, especially within the first 24- 72 hours of initiating therapy or when used in patients at higher risk.

Overdose of codeine in adults has been associated with fatal respiratory depression, and the use of codeine in children younger than 12 years of age has been associated with fatal respiratory depression when used as recommended [see Warnings and Precautions (5.3)]. Accidental ingestion of even one dose of TUXARIN ER, especially by children, can result in respiratory depression and death.

5.3 Ultra-Rapid Metabolism of Codeine and Other Risk Factors for Life-Threatening Respiratory Depression in Children

Life-threatening respiratory depression and death have occurred in children who received codeine. Codeine is subject to variability in metabolism based upon CYP2D6 genotype (described below), which can lead to an increased exposure to the active metabolite morphine. Based upon post-marketing reports, children younger than 12 years old appear to be more susceptible to the respiratory depressant effects of codeine, particularly if there are risk factors for respiratory depression. For example, many reported cases of death occurred in the post-operative period following tonsillectomy and/or adenoidectomy, and many of the children had evidence of being ultra-rapid metabolizers of codeine. Furthermore, children with obstructive sleep apnea who are treated with codeine for post-tonsillectomy and/or adenoidectomy pain may be particularly sensitive to its respiratory depressant effect. Because of the risk of life-threatening respiratory depression and death:

• TUXARIN ER is contraindicated in all children younger than 12 years of age [see Contraindications (4)].
• TUXARIN ER is contraindicated for post-operative management in pediatric patients younger than 18 years of age following tonsillectomy and/or adenoidectomy [see Contraindications (4)].
• Avoid the use of TUXARIN ER in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine. Risk factors include conditions associated with hypoventilation, such as postoperative status, obstructive sleep apnea, obesity, severe pulmonary disease, neuromuscular disease, and concomitant use of other medications that cause respiratory depression. [see Warnings and Precautions (5.9), Use in Specific Populations (8.4)]
• Healthcare providers should choose the lowest effective dose for the shortest period of time and inform patients and caregivers about these risks and the signs of morphine overdose [see Warnings and Precautions (5.1), Overdosage (10)].

5.4 Risks with Use in Pediatric Populations

Children are particularly sensitive to the respiratory depressant effects of codeine [see Warnings and Precautions (5.2, 5.3)]. Because of the risk of life-threatening respiratory depression and death, TUXARIN ER is contraindicated in children less than 12 years of age, and in pediatric patients younger than 18 years of age following tonsillectomy and/or adenoidectomy [see Contraindications (4)].

Use of TUXARIN ER in children also exposes them to the risks of addiction, abuse, and misuse [see Drug Abuse and Dependence (9)], which can lead to overdose and death [see Warnings and Precautions (5.1), Overdosage (10)]. Because the benefits of symptomatic treatment of cough associated with allergies or the common cold do not outweigh the risks of use of codeine in pediatric patients, TUXARIN ER is not indicated for use in patients younger than 18 years of age [see Indications (1), Use in Specific Populations (8.4)].

5.5 Risks with Use in Other At-Risk Populations

5.6 Risk of Accidental Overdose and Death due to Medication Errors

Dosing errors can result in accidental overdose and death. To reduce the risk of overdose and respiratory depression, ensure that the dose of TUXARIN ER is communicated clearly and dispensed accurately [see Dosage and Administration (2.1)].

5.7 Activities Requiring Mental Alertness: Risks of Driving and Operating Machinery

Codeine and chlorpheniramine, the active ingredients in TUXARIN ER, may produce marked drowsiness and impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. Advise patients to avoid engaging in hazardous tasks requiring mental alertness and motor coordination after ingestion of TUXARIN ER. Avoid concurrent use of TUXARIN ER with alcohol or other central nervous system depressants because additional impairment of central nervous system performance may occur [See Warnings and Precautions (5.9)].

5.8 Risks of Interactions with Drugs Affecting Cytochrome P450 Isoenzymes

The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex. Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with TUXARIN ER requires careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine.

5.9 Risks from Concomitant Use with Benzodiazepines or other CNS Depressants

Concomitant use of opioids, including TUXARIN ER, with benzodiazepines, or other CNS depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Because of these risks, avoid use of opioid cough medications in patients taking benzodiazepines, other CNS depressants, or alcohol [see Drug Interactions (7.5)].

Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to use of opioids alone. Because of similar pharmacologic properties, it is reasonable to expect similar risk with concomitant use of opioid cough medications and benzodiazepines, other CNS depressants, or alcohol.

Advise both patients and caregivers about the risks of respiratory depression and sedation if TUXARIN ER is used with benzodiazepines, alcohol, or other CNS depressants [see Patient Counseling Information (17)].

5.10 Risks of Use in Patients with Gastrointestinal Conditions

TUXARIN ER is contraindicated in patients with known or suspected gastrointestinal obstruction, including paralytic ileus [see Contraindications (4)]. The use of codeine in TUXARIN ER may obscure the diagnosis or clinical course of patients with acute abdominal conditions.

The concurrent use of anticholinergics with TUXARIN ER may produce paralytic ileus [see Drug Interactions (7.10)].

The codeine in TUXARIN ER may result in constipation or obstructive bowel disease, especially in patients with underlying intestinal motility disorders. Use with caution in patients with underlying intestinal motility disorders.

The codeine in TUXARIN ER may cause spasm of the sphincter of Oddi, resulting in an increase in biliary tract pressure. Opioids may cause increases in serum amylase [see Warnings and Precautions (5.17)]. Monitor patients with biliary tract disease, including acute pancreatitis for worsening symptoms.

5.11 Risks of Use in Patients with Head Injury, Impaired Consciousness, Increased Intracranial Pressure, or Brain Tumors

Avoid the use of TUXARIN ER in patients with head injury, intracranial lesions, or a pre-existing increase in intracranial pressure. In patients who may be susceptible to the intracranial effects of CO2 retention (e.g., those with evidence of increased intracranial pressure or brain tumors), TUXARIN ER may reduce respiratory drive, and the resultant CO2 retention can further increase intracranial pressure. Furthermore, opioids produce adverse reactions that may obscure the clinical course of patients with head injuries.

5.12 Increased Risk of Seizures in Patients with Seizure Disorders

The codeine and chlorpheniramine in TUXARIN ER may increase the frequency of seizures in patients with seizure disorders, and may increase the risk of seizures occurring in other clinical settings associated with seizures. Monitor patients with a history of seizure disorders for worsened seizure control during TUXARIN ER therapy.

5.13 Co-administration with Monoamine Oxidase Inhibitors (MAOIs)

Concurrent use of TUXARIN ER is contraindicated in patients receiving monoamine oxidase inhibitors (MAOIs) or within 14 days of stopping such therapy [see Contraindications (4)]. MAOIs may potentiate the effects of morphine, codeine's active metabolite, including respiratory depression, coma, and confusion MAOIs [see Drug Interactions (7.7)].

5.14 Severe Hypotension

TUXARIN ER may cause severe hypotension including orthostatic hypotension and syncope in ambulatory patients. There is increased risk in patients whose ability to maintain blood pressure has already been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (e.g., phenothiazines or general anesthetics) [see Drug Interactions (7.5)]. Monitor these patients for signs of hypotension after initiating TUXARIN ER.

In patients with circulatory shock, TUXARIN ER may cause vasodilation that can further reduce cardiac output and blood pressure. Avoid the use of TUXARIN ER in patients with circulatory shock.

5.15 Neonatal Opioid Withdrawal Syndrome

TUXARIN ER is not recommended for use in pregnant women. Prolonged use of TUXARIN ER during pregnancy can result in withdrawal in the neonate. Neonatal opioid withdrawal syndrome, unlike opioid withdrawal syndrome in adults, may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. Observe newborns for signs of neonatal opioid withdrawal syndrome and manage accordingly. Advise pregnant women using opioids for a prolonged period of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available. [see Use in Specific Populations (8.1), Patient Counseling Information (17)]

5.16 Adrenal Insufficiency

Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Presentation of adrenal insufficiency may include non-specific symptoms and signs including nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure. If adrenal insufficiency is suspected, confirm the diagnosis with diagnostic testing as soon as possible. If adrenal insufficiency is diagnosed, treat with physiologic replacement doses of corticosteroids. Wean the patient off of the opioid to allow adrenal function to recover and continue corticosteroid treatment until adrenal function recovers. Other opioids may be tried as some cases reported use of a different opioid without recurrence of adrenal insufficiency. The information available does not identify any particular opioids as being more likely to be associated with adrenal insufficiency.

5.17 Drug/Laboratory Test Interactions

Because opioid agonists may increase biliary tract pressure, with resultant increase in plasma amylase or lipase levels, determination of these enzyme levels may be unreliable for 24 hours after administration of a dose of TUXARIN ER.

7.1 Inhibitors of CYP3A4

The concomitant use of TUXARIN ER with CYP3A4 inhibitors, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g. ketoconazole), or protease inhibitors (e.g., ritonavir), may result in an increase in codeine plasma concentrations with subsequently greater metabolism by cytochrome CYP2D6, resulting in greater morphine levels, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression, particularly when an inhibitor is added after a stable dose of TUXARIN ER is achieved [see Warnings and Precautions (5.8)]. After stopping a CYP3A4 inhibitor, as the effects of the inhibitor decline, it may result in lower codeine levels, greater norcodeine levels, and less metabolism via CYP2D6 with resultant lower morphine levels [see Clinical Pharmacology (12.3)], resulting in decreased opioid efficacy or a withdrawal syndrome in patients who had developed physical dependence to codeine.

Avoid the use of TUXARIN ER while taking a CYP3A4 inhibitor. If concomitant use is necessary, monitor patients for respiratory depression and sedation at frequent intervals.

7.2 CYP3A4 Inducers

The concomitant use of TUXARIN ER and CYP3A4 inducers, such as rifampin, carbamazepine, or phenytoin, can result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology (12.3)], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence [see Warnings and Precautions (5.8)]. After stopping a CYP3A4 inducer, as the effects of the inducer decline, codeine plasma concentrations may increase with subsequently greater metabolism by cytochrome CYP2D6, resulting in greater morphine levels [see Clinical Pharmacology (12.3)], which could increase or prolong both the therapeutic effects and adverse reactions, and may cause serious respiratory depression.

Avoid the use of TUXARIN ER in patients who are taking CYP3A4 inducers. If concomitant use of a CYP3A4 inducer is necessary, follow the patient for reduced efficacy.

7.3 Phenytoin

Adverse event reports in the literature suggest a possible drug interaction involving increased serum phenytoin levels and phenytoin toxicity when chlorpheniramine and phenytoin are co-administered. The exact mechanism for this interaction is not known, however it is believed that chlorpheniramine may inhibit the hepatic metabolism of phenytoin. Avoid the use of TUXARIN ER while taking phenytoin.

7.4 Inhibitors of CYP2D6

Codeine is metabolized by CYP2D6 to form morphine. The concomitant use of TUXARIN ER and CYP2D6 inhibitors, such as paroxetine, fluoxetine, bupropion, or quinidine, can increase the plasma concentration of codeine, but can decrease the plasma concentration of active metabolite morphine, which could result in reduced efficacy [see Clinical Pharmacology (12.3)]. After stopping a CYP2D6 inhibitor, as the effects of the inhibitor decline, the codeine plasma concentration will decrease but the active metabolite morphine plasma concentration will increase, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression [see Clinical Pharmacology (12.3)].

Avoid the use of TUXARIN ER in patients who are taking inhibitors of CYP2D6.

7.5 Benzodiazepines and Other CNS Depressants

Due to additive pharmacologic effect, the concomitant use of benzodiazepines or other CNS depressants, including alcohol, other sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, and other opioids, can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Avoid the use of TUXARIN ER in patients who are taking benzodiazepines or other CNS depressants. [see Warnings and Precautions (5.9)].

7.6 Serotonergic Drugs

The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation. Discontinue TUXARIN ER if serotonin syndrome is suspected.

7.7 Monoamine Oxidase Inhibitors (MAOIs)

TUXARIN ER is contraindicated in patients who are taking MAOIs (i.e., certain drugs used for depression, psychiatric or emotional conditions, or Parkinson's disease) or have taken MAOIs within 14 days [see Contraindications (4)].

MAOI interactions with opioids may manifest as serotonin syndrome or opioid toxicity (e.g., respiratory depression, coma) [see Warnings and Precautions (5.13)].

7.8 Muscle Relaxants

Codeine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. Avoid the use of TUXARIN ER in patients taking muscle relaxants. If concomitant use is necessary, monitor patients for signs of respiratory depression that may be greater than otherwise expected.

7.9 Diuretics

Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Monitor patients for signs of diminished diuresis and/or effects on blood pressure and increase the dosage of the diuretic as needed.

7.10 Anticholinergic Drugs

The concomitant use of anticholinergic drugs with TUXARIN ER may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus [see Warnings and Precautions (5.10)]. Monitor patients for signs of urinary retention or reduced gastric motility when TUXARIN ER is used concomitantly with anticholinergic drugs.

Additive adverse effects resulting from cholinergic blockade (e.g., xerostomia, blurred vision, or constipation) may occur when anticholinergic drugs are administered with chlorpheniramine.

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

8.4 Pediatric Use

TUXARIN ER is not indicated for use in patients younger than 18 years of age because the benefits of symptomatic treatment of cough associated with allergies or the common cold do not outweigh the risks for use of codeine in these patients [see Indications (1), Warnings and Precautions (5.4)].

Life-threatening respiratory depression and death have occurred in children who received codeine [see Warnings and Precautions (5.2)]. In most of the reported cases, these events followed tonsillectomy and/or adenoidectomy, and many of the children had evidence of being ultra-rapid metabolizers of codeine (i.e., multiple copies of the gene for cytochrome P450 isoenzyme 2D6 or high morphine concentrations). Children with sleep apnea may be particularly sensitive to the respiratory depressant effects of codeine.

Because of the risk of life-threatening respiratory depression and death:

• TUXARIN ER is contraindicated in all children younger than 12 years of age [see Contraindications (4)].
• TUXARIN ER is contraindicated for post-operative management in pediatric patients younger than 18 years of age following tonsillectomy and/or adenoidectomy [see Contraindications (4)].
• Avoid the use of TUXARIN ER in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine unless the benefits outweigh the risks. Risk factors include conditions associated with hypoventilation, such as postoperative status, obstructive sleep apnea, obesity, severe pulmonary disease, neuromuscular disease, and concomitant use of other medications that cause respiratory depression. [see Warnings and Precautions (5.3)].

8.5 Geriatric Use

Clinical studies have not been conducted with TUXARIN ER in geriatric populations.

Use caution when considering the use of TUXARIN ER in patients 65 years of age or older. Elderly patients may have increased sensitivity to codeine; greater frequency of decreased hepatic, renal, or cardiac function; or concomitant disease or other drug therapy [see Warnings and Precautions (5.5)].

Respiratory depression is the chief risk for elderly patients treated with opioids, including TUXARIN ER. Respiratory depression has occurred after large initial doses of opioids were administered to patients who were not opioid-tolerant or when opioids were co-administered with other agents that depress respiration [see Warnings and Precautions (5.5, 5.9)].

Codeine 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, monitor these patients closely for respiratory depression, sedation, and hypotension.

8.6 Renal Impairment

The pharmacokinetics of TUXARIN ER has not been characterized in patients with renal impairment. Codeine pharmacokinetics may be altered in patients with renal failure. Clearance may be decreased and the metabolites may accumulate to much higher plasma levels in patients with renal failure as compared to patients with normal renal function. Chlorpheniramine is cleared substantially by the kidney. As such, impaired renal function could potentially lead to the risk of decreased clearance and thereby increased retention or systemic levels of chlorpheniramine. Therefore, TUXARIN ER should be used with caution in patients with severe impairment of renal function, and patients should be monitored closely for signs of hydrocodone toxicity (respiratory depression, sedation, and hypotension) and chlorpheniramine toxicity.

8.7 Hepatic Impairment

No formal studies have been conducted in patients with hepatic impairment so the pharmacokinetics of TUXARIN ER in this patient population are unknown. Chlorpheniramine is extensively metabolized by liver before elimination from the body. As such, impaired hepatic function could potentially lead to the risk of decreased metabolism and thereby increased systemic levels of chlorpheniramine. Therefore, TUXARIN ER should be used with caution in patients with severe impairment of hepatic function, and patients should be monitored closely for signs of hydrocodone toxicity (respiratory depression, sedation, and hypotension) and chlorpheniramine toxicity.

9.1 Controlled Substance

TUXARIN ER contains codeine, a Schedule III controlled substance.

9.2 Abuse

9.3 Dependence

Psychological dependence, physical dependence, and tolerance may develop upon repeated administration of opioids; therefore, TUXARIN ER should be prescribed and administered for the shortest duration that is consistent with individual patient treatment goals and patients should be reevaluated prior to refills [see Dosage and Administration (2.3), Warnings and Precautions (5.1)].

Physical dependence, the condition in which continued administration of the drug is required to prevent the appearance of a withdrawal syndrome, assumes clinically significant proportions only after several weeks of continued oral opioid use, although some mild degree of physical dependence may develop after a few days of opioid therapy.

If TUXARIN ER is abruptly discontinued in a physically-dependent patient, a withdrawal syndrome may occur. Withdrawal also may be precipitated through the administration of drugs with opioid antagonist activity (e.g., naloxone, nalmefene), mixed agonist/antagonist analgesics (e.g., pentazocine, butorphanol, nalbuphine), or partial agonists (e.g., buprenorphine). Some or all of the following can characterize this syndrome: restlessness, lacrimation, rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other signs and symptoms also may develop, including irritability, anxiety, backache, joint pain, weakness, abdominal cramps, insomnia, nausea, anorexia, vomiting, diarrhea, or increased blood pressure, respiratory rate, or heart rate.

Infants born to mothers physically dependent on opioids will also be physically dependent and may exhibit respiratory difficulties and withdrawal signs [see Use in Specific Populations (8.1)].

Clinical Presentation

Treatment of Overdose

Treatment of overdosage is driven by the overall clinical presentation, and consists of discontinuation of TUXARIN ER together with institution of appropriate therapy. Give primary attention to the reestablishment of adequate respiratory exchange through provision of a patent and protected airway and the institution of assisted or controlled ventilation. Employ other supportive measures (including oxygen and vasopressors) in the management of circulatory shock and pulmonary edema as indicated. Cardiac arrest or arrhythmias will require advanced life-support techniques. Gastric emptying may be useful in removing unabsorbed drug.

The opioid antagonists, naloxone and nalmefene, are specific antidotes for respiratory depression resulting from opioid overdose. For clinically significant respiratory or circulatory depression secondary to codeine overdose, administer an opioid antagonist. An antagonist should not be administered in the absence of clinically significant respiratory depression. Because the duration of opioid reversal is expected to be less than the duration of action of codeine in TUXARIN ER, carefully monitor the patient until spontaneous respiration is reliably reestablished. TUXARIN ER will continue to release codeine and add to the codeine load for 4 hours or longer following ingestion, necessitating prolonged monitoring. If the response to an opioid antagonist is suboptimal or only brief in nature, administer additional antagonist as directed by the product's prescribing information.

Hemodialysis is not routinely used to enhance the elimination of codeine or chlorpheniramine from the body.

Urinary excretion of chlorpheniramine is increased when the pH of the urine is acidic; however, acid diuresis is NOT recommended to enhance elimination in overdose, as the risks of acidemia and acute tubular necrosis in patients with rhabdomyolysis far outweigh any potential benefits.

Codeine Phosphate

The chemical name for codeine phosphate is [morphine3methyl ether phosphate (1:1) (salt)] hemihydrate. It has the following structural formula:

Chlorpheniramine Maleate

The chemical name for chlorpheniramine maleate is 2-pyridinepropanamine, γ-(4-chlorophenyl)-N,N-dimethyl-, (Z)-2-butenedioate (1:1). It has the following structural formula:

12.1 Mechanism of Action

12.2 Pharmacodynamics

12.3 Pharmacokinetics

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenicity, mutagenicity, and fertility studies have not been conducted with TUXARIN ER; however, published information is available for the active ingredients.

Store at 20 to 25°C (68 to 77°F) [see USP Controlled Room Temperature].

Dispense in a tight, light-resistant container, as defined in the USP, with a child-resistant closure.

Keep this and all medicine out of reach of children.

Addiction, Abuse, and Misuse

Inform patients that the use of TUXARIN ER, even when taken as recommended, can result in addiction, abuse, and misuse, which can lead to overdose and death [see Warnings and Precautions (5.1)]. Instruct patients not to share TUXARIN ER with others and to take steps to protect TUXARIN ER from theft or misuse.

Important Dosing and Administration Instructions

Advise patients take TUXARIN ER exactly as prescribed. Advise patients not to increase the dose or dosing frequency of TUXARIN ER because serious adverse events such as respiratory depression may occur with overdosage [see Warnings and Precautions (5.2), Overdosage (10)].

Life-Threatening Respiratory Depression

Inform patients of the risk of life-threatening respiratory depression, including information that the risk is greatest when starting TUXARIN ER and that it can occur even at recommended dosages [see Warnings and Precautions (5.2)]. Advise patients how to recognize respiratory depression and to seek medical attention if breathing difficulties develop.

Accidental Ingestion

Inform patients that accidental ingestion, especially by children, may result in respiratory depression or death [see Warnings and Precautions (5.2)]. Instruct patients to take steps to store TUXARIN ER securely and to properly dispose of unused TUXARIN ER in accordance with the local state guidelines and/or regulations.

Ultra-Rapid Metabolism of Codeine and Other Risk Factors for Life-Threatening Respiratory Depression in Children

Advise caregivers that TUXARIN ER is not indicated for pediatric patients under 18 years of age and is contraindicated in all children younger than 12 years of age and in children younger than 18 years of age following tonsillectomy and/or adenoidectomy.

Activities Requiring Mental Alertness

Advise patients to avoid engaging in hazardous tasks that require mental alertness and motor coordination such as operating machinery or driving a motor vehicle as TUXARIN ER may produce marked drowsiness [see Warnings and Precautions (5.7)].

Interactions with Benzodiazepines and Other Central Nervous System Depressants, Including Alcohol

Inform patients and caregivers that potentially fatal additive effects may occur if TUXARIN ER is used with benzodiazepines or other CNS depressants, including alcohol. Advise patients to avoid concomitant use of TUXARIN ER with benzodiazepines or other CNS depressants and to not use alcohol while taking TUXARIN ER [see Warnings and Precautions (5.9), Drug Interactions (7.5)].

Constipation

Advise patients of the potential for severe constipation [see Warnings and Precautions (5.10), Adverse Reactions (6)].

Anaphylaxis

Inform patients that anaphylaxis has been reported with ingredients contained in TUXARIN ER. Advise patients how to recognize such a reaction and when to seek medical attention [see Contraindications (4), Adverse Reactions (6)].

MAOI Interaction

Inform patients not to take TUXARIN ER while using or within 14 days of stopping any drugs that inhibit monoamine oxidase. Patients should not start MAOIs while taking TUXARIN ER [see Warnings and Precautions (5.13), Drug Interactions (7.7)].

Hypotension

Inform patients that TUXARIN ER 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 and Precautions (5.14)].

Pregnancy

Advise patients that use of TUXARIN ER is not recommended during pregnancy [see Use in Specific Populations (8.1)].

Lactation

Advise women that breastfeeding is not recommended during treatment with TUXARIN ER [see Use in Specific Populations (8.2)].

Infertility

Inform patients that chronic use of opioids, such as codeine, a component of TUXARIN ER, may cause reduced fertility. It is not known whether these effects on fertility are reversible [see Use in Specific Populations (8.3)].

Adrenal Insufficiency

Inform patients that TUXARIN ER 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 and Precautions (5.16)].

Serotonin Syndrome

Inform patients that TUXARIN ER 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 physicians if they are taking, or plan to take serotonergic medications. [see Adverse Reactions (6), Drug Interactions (7.6)].

Disposal of Unused TUXARIN ER

Advise patients to properly dispose of unused TUXARIN ER. Advise patients to throw the drug in the household trash following these steps. 1) Remove them from their original containers and mix them with an undesirable substance, such as used coffee grounds or kitty litter (this makes the drug less appealing to children and pets, and unrecognizable to people who may intentionally go through the trash seeking drugs). 2) Place the mixture in a sealable bag, empty can, or other container to prevent the drug from leaking or breaking out of a garbage bag, or to dispose of in accordance with local state guidelines and/or regulations.