TRAMADOL HYDROCHLORIDE

Tramadol hydrochloride tablet, USP is a centrally acting analgesic. The chemical name for tramadol hydrochloride, USP is (±) cis -2-[(dimethylamino)methyl]-1-(3-methoxyphenyl) cyclohexanol hydrochloride. Its structural formula is: Molecular formula is C 16 H 13 NO 2 •HCl The molecular weight of tramadol hydrochloride, USP is 299.8. Tramadol hydrochloride, USP is a white, bitter, crystalline and odorless powder. It is readily soluble in water and ethanol and has a pKa of 9.41. The n-octanol/water log partition coefficient (logP) is 1.35 at pH7. Tramadol hydrochloride tablets, USP for oral administration contain 50 mg of tramadol hydrochloride, USP. In addition, each tablet contains the following inactive ingredients: pregelatinized starch, lactose anhydrous, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, titanium dioxide, hypromellose and polysorbate 80. chemical-structure

Tramadol hydrochloride tablets, USP are indicated for the management of moderate to moderately severe pain in adults.

Adults (17 years of age and over) For patients with moderate to moderately severe chronic pain not requiring rapid onset of analgesic effect, the tolerability of tramadol hydrochloride tablets can be improved by initiating therapy with the following titration regimen: The total daily dose may be increased by 50 mg as tolerated every 3 days to reach 200 mg/day (50 mg q.i.d.). After titration, tramadol hydrochloride tablets 50 mg to 100 mg can be administered as needed for pain relief every four to six hours, not to exceed 400 mg per day. For the subset of patients for whom rapid onset of analgesic effect is required and for whom the benefits outweigh the risk of discontinuation due to adverse events associated with higher initial doses, tramadol hydrochloride tablets 50 mg to 100 mg can be administered as needed for pain relief every four to six hours, not to exceed 400 mg per day. Individualization of Dose Good pain management practice dictates that the dose be individualized according to patient need using the lowest beneficial dose. Studies with tramadol in adults have shown that starting at the lowest possible dose and titrating upward will result in fewer discontinuations and increased tolerability. In all patients with creatinine clearance less than 30 mL/min, it is recommended that the dosing interval of tramadol hydrochloride tablets be increased to 12 hours, with a maximum daily dose of 200 mg. Since only 7% of an administered dose is removed by hemodialysis, dialysis patients can receive their regular dose on the day of dialysis. The recommended dose for adult patients with cirrhosis is 50 mg every 12 hours. In general, dose selection for an elderly patient over 65 years old should be cautious, 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. For elderly patients over 75 years old, total dose should not exceed 300 mg/day.

Tramadol hydrochloride tablets should not be administered to patients who have previously demonstrated hypersensitivity to tramadol, any other component of this product or opioids. Tramadol hydrochloride is contraindicated in any situation where opioids are contraindicated, including acute intoxication with any of the following: alcohol, hypnotics, narcotics, centrally acting analgesics, opioids or psychotropic drugs. Tramadol may worsen central nervous system and respiratory depression in these patients.

Tramadol hydrochloride tablets were administered to 550 patients during the double-blind or open-label extension periods in U.S. studies of chronic nonmalignant pain. Of these patients, 375 were 65 years old or older. Table 2 reports the cumulative incidence rate of adverse reactions by 7, 30, and 90 days for the most frequent reactions (5% or more by 7 days). The most frequently reported events were in the central nervous system and gastrointestinal system. Although the reactions listed in the table are felt to be probably related to tramadol hydrochloride tablets administration, the reported rates also include some events that may have been due to underlying disease or concomitant medication. The overall incidence rates of adverse experiences in these trials were similar for tramadol hydrochloride tablets and the active control groups, TYLENOL ® with codeine #3 (acetaminophen 300 mg with codeine phosphate 30 mg), and aspirin 325 mg with codeine phosphate 30 mg however the rates of withdrawals due to adverse events appeared to be higher in the tramadol hydrochloride groups. [TYLENOL ® is the registered trademark of McNeil Consumer Healthcare and TYLOX ® is the registered trademark of RW Johnson]. Table 2 Cumulative Incidence of Adverse Reactions for Tramadol Hydrochloride Tablets in Chronic Trials of Nonmalignant Pain (N=427) Up to 7 Days Up to 30 Days Up to 90 Days 1 “CNS Stimulation” is a composite of nervousness, anxiety, agitation, tremor, spasticity, euphoria, emotional lability and hallucinations. Dizziness/Vertigo 26% 31% 33% Nausea 24% 34% 40% Constipation 24% 38% 46% Headache 18% 26% 32% Somnolence 16% 23% 25% Vomiting 9% 13% 17% Pruritus 8% 10% 11% “CNS Stimulation” 1 7% 11% 14% Asthenia 6% 11% 12% Sweating 6% 7% 9% Dyspepsia 5% 9% 13% Dry Mouth 5% 9% 10% Diarrhea 5% 6% 10% Incidence 1% to less than 5%, possibly causally related: the following lists adverse reactions that occurred with an incidence of 1% to less than 5% in clinical trials, and for which the possibility of a causal relationship with tramadol hydrochloride tablets exists. Body as a Whole: Malaise. Cardiovascular: Vasodilation. Central Nervous System: Anxiety, Confusion, Coordination disturbance, Euphoria, Miosis, Nervousness, Sleep disorder. Gastrointestinal: Abdominal pain, Anorexia, Flatulence. Musculoskeletal: Hypertonia. Skin: Rash. Special Senses: Visual disturbance. Urogenital: Menopausal symptoms, Urinary frequency, Urinary retention. Incidence less than 1%, possibly causally related: the following lists adverse reactions that occurred with an incidence of less than 1% in clinical trials and/or reported in post-marketing experience. Body as a Whole: Accidental injury, Allergic reaction, Anaphylaxis, Death, Suicidal tendency, Weight loss, Serotonin syndrome (mental status change, hyperreflexia, fever, shivering, tremor, agitation, diaphoresis, seizures and coma). Cardiovascular: Orthostatic hypotension, Syncope, Tachycardia. Central Nervous System: Abnormal gait, Amnesia, Cognitive dysfunction, Depression, Difficulty in concentration, Hallucinations, Paresthesia, Seizure (see WARNINGS ), Tremor. Respiratory: Dyspnea. Skin: Stevens-Johnson syndrome/Toxic epidermal necrolysis, Urticaria, Vesicles. Special Senses: Dysgeusia. Urogenital: Dysuria, Menstrual disorder. Other adverse experiences, causal relationship unknown: A variety of other adverse events were reported infrequently in patients taking tramadol hydrochloride tablets during clinical trials and/or reported in post-marketing experience. A causal relationship between tramadol hydrochloride tablets and these events has not been determined. However, the most significant events are listed below as alerting information to the physician. Cardiovascular: Abnormal ECG, Hypertension, Hypotension, Myocardial ischemia, Palpitations, Pulmonary edema, Pulmonary embolism. Central Nervous System: Migraine, Speech disorders. Gastrointestinal: Gastrointestinal bleeding, Hepatitis, Stomatitis, Liver failure. Laboratory Abnormalities: Creatinine increase, Elevated liver enzymes, Hemoglobin decrease, Proteinuria. Sensory: Cataracts, Deafness, Tinnitus.

CYP2D6 and CYP3A4 Inhibitors Concomitant administration of CYP2D6 and/or CYP3A4 inhibitors (see CLINICAL PHARMACOLOGY, Pharmacokinetics ), such as quinidine, fluoxetine, paroxetine and amitriptyline (CYP2D6 inhibitors), and ketoconazole and erythromycin (CYP3A4 inhibitors), may reduce metabolic clearance of tramadol increasing the risk for serious adverse events including seizures and serotonin syndrome. Serotonergic Drugs There have been postmarketing reports of serotonin syndrome with use of tramadol and SSRIs/SNRIs or MAOIs and α2-adrenergic blockers. Caution is advised when tramadol hydrochloride tablet is coadministered with other drugs that may affect the serotonergic neurotransmitter systems, such as SSRIs, MAOIs, triptans, linezolid (an antibiotic which is a reversible non-selective MAOI), lithium, or St. John's Wort. If concomitant treatment of tramadol hydrochloride tablet with a drug affecting the serotonergic neurotransmitter system is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases (see WARNINGS, Serotonin Syndrome ). Triptans Based on the mechanism of action of tramadol and the potential for serotonin syndrome, caution is advised when tramadol hydrochloride tablet is coadministered with a triptan. If concomitant treatment of tramadol hydrochloride tablet with a triptan is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases (see WARNINGS, Serotonin Syndrome ). Use with Carbamazepine Patients taking carbamazepine may have a significantly reduced analgesic effect of tramadol hydrochloride tablets. Because carbamazepine increases tramadol metabolism and because of the seizure risk associated with tramadol, concomitant administration of tramadol hydrochloride tablets and carbamazepine is not recommended. Use with Quinidine Tramadol is metabolized to M1 by CYP2D6. Quinidine is a selective inhibitor of that isoenzyme, so that concomitant administration of quinidine and tramadol hydrochloride tablets results in increased concentrations of tramadol and reduced concentrations of M1. The clinical consequences of these findings are unknown. In vitro drug interaction studies in human liver microsomes indicate that tramadol has no effect on quinidine metabolism. Potential for Other Drugs to Affect Tramadol In vitro drug interaction studies in human liver microsomes indicate that concomitant administration with inhibitors of CYP2D6 such as fluoxetine, paroxetine, and amitriptyline could result in some inhibition of the metabolism of tramadol. Administration of CYP3A4 inhibitors, such as ketoconazole and erythromycin, or inducers, such as rifampin and St. John's Wort, with tramadol hydrochloride tablet may affect the metabolism of tramadol leading to altered tramadol exposure. Potential for Tramadol to Affect Other Drugs In vitro studies indicate that tramadol is unlikely to inhibit the CYP3A4-mediated metabolism of other drugs when tramadol is administered concomitantly at therapeutic doses. Tramadol does not appear to induce its own metabolism in humans, since observed maximal plasma concentrations after multiple oral doses are higher than expected based on single-dose data. Tramadol is a mild inducer of selected drug metabolism pathways measured in animals. Use with Cimetidine Concomitant administration of tramadol hydrochloride tablets with cimetidine does not result in clinically significant changes in tramadol pharmacokinetics. Therefore, no alteration of the tramadol hydrochloride tablets dosage regimen is recommended. Use with Digoxin and Warfarin Post-marketing surveillance has revealed rare reports of digoxin toxicity and alteration of warfarin effect, including elevation of prothrombin times.