Ultracet® (tramadol hydrochloride/acetaminophen) Tablets combines two analgesics, tramadol 37.5 mg and acetaminophen 325 mg.
The chemical name for tramadol hydrochloride is (±)cis-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl) cyclohexanol hydrochloride. Its structural formula is:
The molecular weight of tramadol hydrochloride is 299.84. Tramadol hydrochloride is a white, bitter, crystalline, and odorless powder.
The chemical name for acetaminophen is N-acetyl-p-aminophenol. Its structural formula is:
The molecular weight of acetaminophen is 151.17. Acetaminophen is an analgesic and antipyretic agent which occurs as a white, odorless, crystalline powder, possessing a slightly bitter taste.
Ultracet® tablets contain 37.5 mg tramadol hydrochloride and 325 mg acetaminophen and are light yellow in color. Inactive ingredients in the tablet are powdered cellulose, pregelatinized corn starch, sodium starch glycolate, corn starch, magnesium stearate, hypromellose, polyethylene glycol, polysorbate 80, titanium dioxide, iron oxide, and carnauba wax.
Ultracet - Clinical Pharmacology
The following information is based on studies of tramadol alone or acetaminophen alone, except where otherwise noted:
Pharmacodynamics
Ultracet® contains tramadol and acetaminophen. Tramadol is a centrally acting synthetic opioid analgesic. Although its mode of action is not completely understood, from animal tests, at least two complementary mechanisms appear applicable: binding of parent and M1 metabolite to µ-opioid receptors and weak inhibition of reuptake of norepinephrine and serotonin.
Opioid activity is due to both low affinity binding of the parent compound and higher affinity binding of the O-demethylated metabolite M1 to µ-opioid receptors. In animal models, M1 is up to 6 times more potent than tramadol in producing analgesia and 200 times more potent in µ-opioid binding. Tramadol-induced analgesia is only partially antagonized by the opiate antagonist naloxone in several animal tests. The relative contribution of both tramadol and M1 to human analgesia is dependent upon the plasma concentrations of each compound (see CLINICAL PHARMACOLOGY, Pharmacokinetics).
Tramadol has been shown to inhibit reuptake of norepinephrine and serotonin in vitro, as have some other opioid analgesics. These mechanisms may contribute independently to the overall analgesic profile of tramadol.
Apart from analgesia, tramadol administration may produce a constellation of symptoms (including dizziness, somnolence, nausea, constipation, sweating, and pruritus) similar to that of other opioids.
Acetaminophen is a non-opiate, non-salicylate analgesic.
Pharmacokinetics
Tramadol is administered as a racemate and both the [-] and [+] forms of both tramadol and M1 are detected in the circulation. The pharmacokinetics of plasma tramadol and acetaminophen following oral administration of one Ultracet® tablet are shown in Table 1. Tramadol has a slower absorption and longer half-life when compared to acetaminophen.
Table 1: Summary of Mean (±SD) Pharmacokinetic Parameters of the (+)- and (-) Enantiomers of Tramadol and M1 and Acetaminophen Following A Single Oral Dose Of One Tramadol/Acetaminophen Combination Tablet (37.5 mg/325 mg) in Volunteers
| Parameter |
(+)-Tramadol |
(-)-Tramadol |
(+)-M1 |
(-)-M1 |
acetaminophen |
|---|
|
| Cmax (ng/mL) |
64.3 |
(9.3) |
55.5 |
(8.1) |
10.9 |
(5.7) |
12.8 |
(4.2) |
4.2 |
(0.8) |
| tmax (h) |
1.8 |
(0.6) |
1.8 |
(0.7) |
2.1 |
(0.7) |
2.2 |
(0.7) |
0.9 |
(0.7) |
| CL/F (mL/min) |
588 |
(226) |
736 |
(244) |
- |
- |
- |
- |
365 |
(84) |
| t1/2 (h) |
5.1 |
(1.4) |
4.7 |
(1.2) |
7.8 |
(3.0) |
6.2 |
(1.6) |
2.5 |
(0.6) |
A single-dose pharmacokinetic study of Ultracet® in volunteers showed no drug interactions between tramadol and acetaminophen. Upon multiple oral dosing to steady state, however, the bioavailability of tramadol and metabolite M1 was lower for the combination tablets compared to tramadol administered alone. The decrease in AUC was 14% for (+)-tramadol, 10.4% for (-)-tramadol, 11.9% for (+)-M1, and 24.2% for (-)-M1. The cause of this reduced bioavailability is not clear. Following single- or multiple-dose administration of Ultracet®, no significant change in acetaminophen pharmacokinetics was observed when compared to acetaminophen given alone.
AbsorptionThe absolute bioavailability of tramadol from Ultracet® tablets has not been determined. Tramadol hydrochloride has a mean absolute bioavailability of approximately 75% following administration of a single 100 mg oral dose of ULTRAM® tablets. The mean peak plasma concentration of racemic tramadol and M1 after administration of two Ultracet® tablets occurs at approximately two and three hours, respectively, post-dose.
Peak plasma concentrations of acetaminophen occur within one hour and are not affected by co-administration with tramadol. Oral absorption of acetaminophen following administration of Ultracet® occurs primarily in the small intestine.
Food EffectsWhen Ultracet® was administered with food, the time to peak plasma concentration was delayed for approximately 35 minutes for tramadol and almost one hour for acetaminophen. However, peak plasma concentrations, and the extents of absorption, of tramadol and acetaminophen were not affected. The clinical significance of this difference is unknown.
DistributionThe volume of distribution of tramadol was 2.6 and 2.9 L/kg in male and female subjects, respectively, following a 100 mg intravenous dose. The binding of tramadol to human plasma proteins is approximately 20% and binding also appears to be independent of concentration up to 10 µg/mL. Saturation of plasma protein binding occurs only at concentrations outside the clinically relevant range.
Acetaminophen appears to be widely distributed throughout most body tissues except fat. Its apparent volume of distribution is about 0.9 L/kg. A relative small portion (~20%) of acetaminophen is bound to plasma protein.
MetabolismFollowing oral administration, tramadol is extensively metabolized by a number of pathways, including CYP2D6 and CYP3A4, as well as by conjugation of parent and metabolites. Approximately 30% of the dose is excreted in the urine as unchanged drug, whereas 60% of the dose is excreted as metabolites. The major metabolic pathways appear to be N- and O- demethylation and glucuronidation or sulfation in the liver. Metabolite M1 (O-desmethyltramadol) is pharmacologically active in animal models. Formation of M1 is dependent on CYP2D6 and as such is subject to inhibition, which may affect the therapeutic response (see PRECAUTIONS, Drug Interactions).
Approximately 7% of the population has reduced activity of the CYP2D6 isoenzyme of cytochrome P450. These individuals are "poor metabolizers" of debrisoquine, dextromethorphan, and tricyclic antidepressants, among other drugs. Based on a population PK analysis of Phase 1 studies in healthy subjects, concentrations of tramadol were approximately 20% higher in "poor metabolizers" versus "extensive metabolizers," while M1 concentrations were 40% lower. In vitro drug interaction studies in human liver microsomes indicate that inhibitors of CYP2D6 such as fluoxetine and its metabolite norfluoxetine, amitriptyline, and quinidine inhibit the metabolism of tramadol to various degrees. The full pharmacological impact of these alterations in terms of either efficacy or safety is unknown. Concomitant use of SEROTONIN re-uptake INHIBITORS and MAO INHIBITORS may enhance the risk of adverse events, including seizure (see WARNINGS) and serotonin syndrome.
Acetaminophen is primarily metabolized in the liver by first-order kinetics and involves three principal separate pathways:
- a)
- conjugation with glucuronide;
- b)
- conjugation with sulfate; and
- c)
- oxidation via the cytochrome, P450-dependent, mixed-function oxidase enzyme pathway to form a reactive intermediate metabolite, which conjugates with glutathione and is then further metabolized to form cysteine and mercapturic acid conjugates. The principal cytochrome P450 isoenzyme involved appears to be CYP2E1, with CYP1A2 and CYP3A4 as additional pathways.
In adults, the majority of acetaminophen is conjugated with glucuronic acid and, to a lesser extent, with sulfate. These glucuronide-, sulfate-, and glutathione-derived metabolites lack biologic activity. In premature infants, newborns, and young infants, the sulfate conjugate predominates.
EliminationTramadol is eliminated primarily through metabolism by the liver and the metabolites are eliminated primarily by the kidneys. The plasma elimination half-lives of racemic tramadol and M1 are approximately 5–6 and 7 hours, respectively, after administration of Ultracet®. The apparent plasma elimination half-life of racemic tramadol increased to 7–9 hours upon multiple dosing of Ultracet®.
The half-life of acetaminophen is about 2 to 3 hours in adults. It is somewhat shorter in children and somewhat longer in neonates and in cirrhotic patients. Acetaminophen is eliminated from the body primarily by formation of glucuronide and sulfate conjugates in a dose-dependent manner. Less than 9% of acetaminophen is excreted unchanged in the urine.
Special Populations
RenalThe pharmacokinetics of Ultracet® in patients with renal impairment has not been studied. Based on studies using tramadol alone, excretion of tramadol and metabolite M1 is reduced in patients with creatinine clearance of less than 30 mL/min. Adjustment of dosing regimen in this patient population is recommended (see DOSAGE AND ADMINISTRATION). The total amount of tramadol and M1 removed during a 4-hour dialysis period is less than 7% of the administered dose based on studies using tramadol alone.
HepaticThe pharmacokinetics and tolerability of Ultracet® in patients with impaired hepatic function have not been studied. Since tramadol and acetaminophen are both extensively metabolized by the liver, the use of Ultracet® in patients with hepatic impairment is not recommended (see PRECAUTIONS and DOSAGE AND ADMINISTRATION).
GeriatricA population pharmacokinetic analysis of data obtained from a clinical trial in patients with chronic pain treated with Ultracet®, which included 55 patients between 65 and 75 years of age and 19 patients over 75 years of age, showed no significant changes in the pharmacokinetics of tramadol and acetaminophen in elderly patients with normal renal and hepatic function (see PRECAUTIONS, Geriatric Use).
GenderTramadol clearance was 20% higher in female subjects compared to males on four phase I studies of Ultracet® in 50 male and 34 female healthy subjects. The clinical significance of this difference is unknown.
PediatricThe pharmacokinetics of Ultracet® tablets has not been studied in pediatric patients below 16 years of age.
Clinical Studies
Single-Dose Studies for Treatment of Acute Pain
In pivotal single-dose studies in acute pain, two tablets of Ultracet® administered to patients with pain following oral surgical procedures provided greater relief than placebo or either of the individual components given at the same dose. The onset of pain relief after Ultracet® was faster than tramadol alone. Onset of analgesia occurred in less than one hour. The duration of pain relief after Ultracet® was longer than acetaminophen alone. Analgesia was generally comparable to that of the comparator, ibuprofen.
Indications and Usage for Ultracet
Ultracet® is indicated for the short-term (five days or less) management of acute pain.
Contraindications
Ultracet® should not be administered to patients who have previously demonstrated hypersensitivity to tramadol, acetaminophen, any other component of this product, or opioids. Ultracet® 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. Ultracet® may worsen central nervous system and respiratory depression in these patients.
Warnings
Hepatotoxicity
Ultracet® contains tramadol HCl and acetaminophen. Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4,000 milligrams per day, and often involve more than one acetaminophen-containing product. The excessive intake of acetaminophen may be intentional to cause self-harm or unintentional as patients attempt to obtain more pain relief or unknowingly take other acetaminophen-containing products (see Boxed Warning).
The risk of acute liver failure is higher in individuals with underlying liver disease and in individuals who ingest alcohol while taking acetaminophen.
Instruct patients to look for acetaminophen or APAP on package labels and not to use more than one product that contains acetaminophen. Instruct patients to seek medical attention immediately upon ingestion of more than 4,000 milligrams of acetaminophen per day, even if they feel well.
Seizure Risk
Seizures have been reported in patients receiving tramadol within the recommended dosage range. Spontaneous post-marketing reports indicate that seizure risk is increased with doses of tramadol above the recommended range. Concomitant use of tramadol increases the seizure risk in patients taking:
- Selective serotonin reuptake inhibitors (SSRI antidepressants or anorectics),
- Tricyclic antidepressants (TCAs), and other tricyclic compounds (e.g., cyclobenzaprine, promethazine, etc.), or
- Other opioids.
Administration of tramadol may enhance the seizure risk in patients taking:
- MAO inhibitors (see also WARNINGS, Use with MAO Inhibitors and Serotonin Re-uptake Inhibitors),
- Neuroleptics, or
- Other drugs that reduce the seizure threshold.
Risk of convulsions may also increase in patients with epilepsy, those with a history of seizures, or in patients with a recognized risk for seizure (such as head trauma, metabolic disorders, alcohol and drug withdrawal, or CNS infections). In tramadol overdose, naloxone administration may increase the risk of seizure.
Suicide Risk
- Do not prescribe Ultracet® for patients who are suicidal or addiction-prone.
- Prescribe Ultracet® with caution for patients taking tranquilizers or antidepressant drugs and patients who use alcohol in excess and who suffer from emotional disturbance or depression.
The judicious prescribing of tramadol is essential to the safe use of this drug. With patients who are depressed or suicidal, consideration should be given to the use of non-narcotic analgesics.
Tramadol-related deaths have occurred in patients with previous histories of emotional disturbances or suicidal ideation or attempts as well as histories of misuse of tranquilizers, alcohol, and other CNS-active drugs (see WARNINGS, Risk of Overdosage).
Serotonin Syndrome Risk
The development of a potentially life-threatening serotonin syndrome may occur with the use of tramadol products, including Ultracet®, particularly with concomitant use of serotonergic drugs such as SSRIs, SNRIs, TCAs, MAOIs, and triptans, with drugs which impair metabolism of serotonin (including MAOIs), and with drugs which impair metabolism of tramadol (CYP2D6 and CYP3A4 inhibitors). This may occur within the recommended dose (see CLINICAL PHARMACOLOGY, Pharmacokinetics).
Serotonin syndrome may include mental-status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination), and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).
Hypersensitivity/Anaphylaxis
Serious and rarely fatal anaphylactic reactions have been reported in patients receiving therapy with tramadol. When these events do occur it is often following the first dose. Other reported allergic reactions include pruritus, hives, bronchospasm, angioedema, toxic epidermal necrolysis, and Stevens-Johnson syndrome. Patients with a history of anaphylactoid reactions to codeine and other opioids may be at increased risk and therefore should not receive Ultracet® (see CONTRAINDICATIONS).
There have been post-marketing reports of hypersensitivity and anaphylaxis associated with the use of acetaminophen. Clinical signs included swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting. There were infrequent reports of life-threatening anaphylaxis requiring emergency medical attention. Instruct patients to discontinue Ultracet® immediately and seek medical care if they experience these symptoms. Do not prescribe Ultracet® for patients with acetaminophen allergy.
Respiratory Depression
Administer Ultracet® cautiously in patients at risk for respiratory depression. In these patients, alternative non-opioid analgesics should be considered. When large doses of tramadol are administered with anesthetic medications or alcohol, respiratory depression may result. Respiratory depression should be treated as an overdose. If naloxone is to be administered, use cautiously because it may precipitate seizures (see WARNINGS, Seizure Risk and OVERDOSAGE).
Interaction With Central Nervous System (CNS) Depressants
Ultracet® should be used with caution and in reduced dosages when administered to patients receiving CNS depressants such as alcohol, opioids, anesthetic agents, narcotics, phenothiazines, tranquilizers, or sedative hypnotics. Tramadol increases the risk of CNS and respiratory depression in these patients.
Interactions With Alcohol and Drugs of Abuse
Tramadol may be expected to have additive effects when used in conjunction with alcohol, other opioids, or illicit drugs that cause central nervous system depression.
Increased Intracranial Pressure or Head Trauma
Ultracet® should be used with caution in patients with increased intracranial pressure or head injury. The respiratory depressant effects of opioids include carbon dioxide retention and secondary elevation of cerebrospinal fluid pressure and may be markedly exaggerated in these patients. Additionally, pupillary changes (miosis) from tramadol may obscure the existence, extent, or course of intracranial pathology. Clinicians should also maintain a high index of suspicion for adverse drug reactions when evaluating altered mental status in these patients if they are receiving Ultracet® (see WARNINGS, Respiratory Depression).
Use in Ambulatory Patients
Tramadol may impair the mental and or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. The patient using this drug should be cautioned accordingly.
Use With MAO Inhibitors and Serotonin Re-uptake Inhibitors
Use Ultracet® with great caution in patients taking monoamine oxidase inhibitors. Animal studies have shown increased deaths with combined administration of MAO inhibitors and tramadol. Concomitant use of tramadol with MAO inhibitors or SSRIs increases the risk of adverse events, including seizure and serotonin syndrome.
Use With Alcohol
Ultracet® should not be used concomitantly with alcohol consumption. The use of Ultracet® in patients with liver disease is not recommended.
Use With Other Acetaminophen-containing Products
Due to the potential for acetaminophen hepatotoxicity at doses higher than the recommended dose, Ultracet® should not be used concomitantly with other acetaminophen-containing products.
Misuse, Abuse and Diversion
Tramadol has mu-opioid agonist activity. Ultracet®, a tramadol-containing product, can be sought by drug abusers and people with addiction disorders and may be subject to criminal diversion. The possibility of illegal or illicit use should be considered when prescribing or dispensing Ultracet® in situations where the physician or pharmacist is concerned about an increased risk of misuse, abuse, or diversion. Misuse or abuse poses a significant risk to the abuser that could result in overdose and death (see DRUG ABUSE AND DEPENDENCE and OVERDOSAGE).
Concerns about abuse, addiction, and diversion should not prevent the proper management of pain. The development of addiction to opioid analgesics in properly managed patients with pain has been reported to be rare. However, data are not available to establish the true incidence of addiction in chronic pain patients.
Risk of Overdosage
Patients taking tramadol should be warned not to exceed the dose recommended by their physician. Tramadol products in excessive doses, either alone or in combination with other CNS depressants, including alcohol, are a cause of drug-related deaths. Patients should be cautioned about the concomitant use of tramadol products and alcohol because of potentially serious CNS additive effects of these agents. Because of its added depressant effects, tramadol should be prescribed with caution for those patients whose medical condition requires the concomitant administration of sedatives, tranquilizers, muscle relaxants, tricyclic antidepressants, or other CNS depressant drugs. Patients should be advised of the additive depressant effects of these combinations.
Serious potential consequences of overdosage with tramadol are central nervous system depression, respiratory depression, and death. Some deaths have occurred as a consequence of the accidental ingestion of excessive quantities of tramadol alone or in combination with other drugs. In treating an overdose, primary attention should be given to maintaining adequate ventilation along with general supportive treatment (see OVERDOSAGE).
A serious potential consequence of overdosage with acetaminophen is hepatic (centrilobular) necrosis, leading to hepatic failure and death. Emergency help should be sought immediately and treatment initiated immediately if overdose is suspected, even if symptoms are not apparent.
Withdrawal
Withdrawal symptoms may occur if Ultracet® is discontinued abruptly (see also DRUG ABUSE AND DEPENDENCE). Reported symptoms have included anxiety, sweating, insomnia, rigors, pain, nausea, tremors, diarrhea, upper respiratory symptoms, piloerection, and rarely hallucinations. Other symptoms that have been reported less frequently with Ultracet® discontinuation include: panic attacks, severe anxiety, and paresthesias. Clinical experience suggests that withdrawal symptoms may be avoided by tapering Ultracet® at the time of discontinuation.
Precautions
General
The recommended dose of Ultracet® should not be exceeded.
Do not co-administer Ultracet® with other tramadol or acetaminophen-containing products (see WARNINGS, Use With Other Acetaminophen-containing Products and Risk of Overdosage).
Pediatric Use
The safety and effectiveness of Ultracet® has not been studied in the pediatric population.
Geriatric Use
In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function; of concomitant disease; and multiple drug therapy.
Acute Abdominal Conditions
The administration of Ultracet® may complicate the clinical assessment of patients with acute abdominal conditions.
Use in Renal Disease
Ultracet® has not been studied in patients with impaired renal function. Experience with tramadol suggests that impaired renal function results in a decreased rate and extent of excretion of tramadol and its active metabolite, M1. In patients with creatinine clearances of less than 30 mL/min, it is recommended that the dosing interval of Ultracet® be increased, not to exceed 2 tablets every 12 hours.
Use in Hepatic Disease
Ultracet® has not been studied in patients with impaired hepatic function. The use of Ultracet® in patients with hepatic impairment is not recommended (see WARNINGS, Use With Alcohol).
Information for Patients
- Do not take Ultracet® if you are allergic to any of its ingredients.
- If you develop signs of allergy such as a rash or difficulty breathing, stop taking Ultracet® and contact your healthcare provider immediately.
- Do not take more than 4,000 milligrams of acetaminophen per day. Call your doctor if you took more than the recommended dose.
- Do not take Ultracet® in combination with other tramadol or acetaminophen-containing products, including over-the-counter preparations.
- Ultracet® may cause seizures and/or serotonin syndrome with concomitant use of serotonergic agents (including SSRIs, SNRIs, and triptans) or drugs that significantly reduce the metabolic clearance of tramadol.
- Ultracet® may impair mental or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery.
- Ultracet® should not be taken concomitantly with alcohol-containing beverages during the course of treatment with Ultracet®.
- Ultracet® should be used with caution when taking medications such as tranquilizers, hypnotics, or other opiate-containing analgesics.
- Inform the physician if you are pregnant, think you might become pregnant, or are trying to become pregnant (see PRECAUTIONS, Labor and Delivery).
- Understand the single-dose and 24-hour dose limit and the time interval between doses, since exceeding these recommendations can result in respiratory depression, seizures, hepatic toxicity, and death.
Drug Interactions
CYP2D6 and CYP3A4 InhibitorsConcomitant 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 DrugsThere have been postmarketing reports of serotonin syndrome with use of tramadol and SSRIs/SNRIs or MAOIs and α2-adrenergic blockers. Caution is advised when Ultracet® 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 Ultracet® 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).
TriptansBased on the mechanism of action of tramadol and the potential for serotonin syndrome, caution is advised when Ultracet® is coadministered with a triptan. If concomitant treatment of Ultracet® 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 CarbamazepinePatients taking carbamazepine may have a significantly reduced analgesic effect of tramadol. Because carbamazepine increases tramadol metabolism and because of the seizure risk associated with tramadol, concomitant administration of Ultracet® and carbamazepine is not recommended.
Use With QuinidineTramadol is metabolized to M1 by CYP2D6. Quinidine is a selective inhibitor of that isoenzyme; so that concomitant administration of quinidine and tramadol 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 TramadolIn 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 Ultracet® may affect the metabolism of tramadol, leading to altered tramadol exposure.
Potential for Tramadol to Affect Other DrugsIn 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 CimetidineConcomitant administration of Ultracet® and cimetidine has not been studied. Concomitant administration of tramadol and cimetidine does not result in clinically significant changes in tramadol pharmacokinetics. Therefore, no alteration of the Ultracet® dosage regimen is recommended.
Use With DigoxinPost-marketing surveillance of tramadol has revealed rare reports of digoxin toxicity.
Use With Warfarin-Like CompoundsPost-marketing surveillance of both tramadol and acetaminophen individual products have revealed rare alterations of warfarin effect, including elevation of prothrombin times.
While such changes have been generally of limited clinical significance for the individual products, periodic evaluation of prothrombin time should be performed when Ultracet® and warfarin-like compounds are administered concurrently.
Carcinogenesis, Mutagenesis, Impairment of Fertility
There are no animal or laboratory studies on the combination product (tramadol and acetaminophen) to evaluate carcinogenesis, mutagenesis, or impairment of fertility.
A slight but statistically significant increase in two common murine tumors, pulmonary and hepatic, was observed in a mouse carcinogenicity study, particularly in aged mice. Mice were dosed orally up to 30 mg/kg (90 mg/m2 or 0.5 times the maximum daily human tramadol dosage of 185 mg/m2) for approximately two years, although the study was not done with the Maximum Tolerated Dose. This finding is not believed to suggest risk in humans. No such finding occurred in a rat carcinogenicity study (dosing orally up to 30 mg/kg, 180 mg/m2, or 1 time the maximum daily human tramadol dosage).
Tramadol was not mutagenic in the following assays: Ames Salmonella microsomal activation test, CHO/HPRT mammalian cell assay, mouse lymphoma assay (in the absence of metabolic activation), dominant lethal mutation tests in mice, chromosome aberration test in Chinese hamsters, and bone marrow micronucleus tests in mice and Chinese hamsters. Weakly mutagenic results occurred in the presence of metabolic activation in the mouse lymphoma assay and micronucleus test in rats. Overall, the weight of evidence from these tests indicates that tramadol does not pose a genotoxic risk to humans.
No effects on fertility were observed for tramadol at oral dose levels up to 50 mg/kg (350 mg/m2) in male rats and 75 mg/kg (450 mg/m2) in female rats. These dosages are 1.6 and 2.4 times the maximum daily human tramadol dosage of 185 mg/m2.
Pregnancy
Teratogenic Effects Pregnancy Category C
No drug-related teratogenic effects were observed in the progeny of rats treated orally with tramadol and acetaminophen. The tramadol/acetaminophen combination product was shown to be embryotoxic and fetotoxic in rats at a maternally toxic dose, 50/434 mg/kg tramadol/acetaminophen (300/2604 mg/m2 or 1.6 times the maximum daily human tramadol/acetaminophen dosage of 185/1591 mg/m2), but was not teratogenic at this dose level. Embryo and fetal toxicity consisted of decreased fetal weights and increased supernumerary ribs.
Non-teratogenic EffectsTramadol alone was evaluated in peri- and post-natal studies in rats. Progeny of dams receiving oral (gavage) dose levels of 50 mg/kg (300 mg/m2 or 1.6 times the maximum daily human tramadol dosage) or greater had decreased weights, and pup survival was decreased early in lactation at 80 mg/kg (480 mg/m2 or 2.6 times the maximum daily human tramadol dosage).
There are no adequate and well-controlled studies in pregnant women. Ultracet® should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Neonatal seizures, neonatal withdrawal syndrome, fetal death and stillbirth have been reported with tramadol hydrochloride during post-marketing.
Labor and Delivery
Ultracet® should not be used in pregnant women prior to or during labor unless the potential benefits outweigh the risks. Safe use in pregnancy has not been established. Chronic use during pregnancy may lead to physical dependence and post-partum withdrawal symptoms in the newborn (see DRUG ABUSE AND DEPENDENCE). Tramadol has been shown to cross the placenta. The mean ratio of serum tramadol in the umbilical veins compared to maternal veins was 0.83 for 40 women given tramadol during labor.
The effect of Ultracet®, if any, on the later growth, development, and functional maturation of the child is unknown.
Nursing Mothers
Ultracet® is not recommended for obstetrical preoperative medication or for post-delivery analgesia in nursing mothers because its safety in infants and newborns has not been studied.
Following a single IV 100 mg dose of tramadol, the cumulative excretion in breast milk within 16 hours post-dose was 100 µg of tramadol (0.1% of the maternal dose) and 27 µg of M1.
Adverse Reactions
Table 2 reports the incidence rate of treatment-emergent adverse events over five days of Ultracet® use in clinical trials (subjects took an average of at least 6 tablets per day).
Table 2: Incidence of Treatment-Emergent Adverse Events (≥2.0%)
Body System
Preferred Term |
Ultracet® (N=142)
(%) |
|---|
|
| Gastrointestinal System Disorders |
|
| Constipation |
6 |
| Diarrhea |
3 |
| Nausea |
3 |
| Dry Mouth |
2 |
| Psychiatric Disorders |
|
| Somnolence |
6 |
| Anorexia |
3 |
| Insomnia |
2 |
| Central & Peripheral Nervous System |
|
| Dizziness |
3 |
| Skin and Appendages |
|
| Sweating Increased |
4 |
| Pruritus |
2 |
| Reproductive Disorders, Male |
|
| Prostatic Disorder |
2 |
Incidence at least 1%, causal relationship at least possible or greater: the following lists adverse reactions that occurred with an incidence of at least 1% in single-dose or repeated-dose clinical trials of Ultracet®.
Body as a Whole – Asthenia, fatigue, hot flushes
Central and Peripheral Nervous System – Dizziness, headache, tremor
Gastrointestinal System – Abdominal pain, constipation, diarrhea, dyspepsia, flatulence, dry mouth, nausea, vomiting
Psychiatric Disorders – Anorexia, anxiety, confusion, euphoria, insomnia, nervousness, somnolence
Skin and Appendages – Pruritus, rash, increased sweating
Selected Adverse events occurring at less than 1%: the following lists clinically relevant adverse reactions that occurred with an incidence of less than 1% in Ultracet® clinical trials.
Body as a Whole – Chest pain, rigors, syncope, withdrawal syndrome
Cardiovascular Disorders – Hypertension, aggravated hypertension, hypotension
Central and Peripheral Nervous System – Ataxia, convulsions, hypertonia, migraine, aggravated migraine, involuntary muscle contractions, paresthesias, stupor, vertigo
Gastrointestinal System – Dysphagia, melena, tongue edema
Hearing and Vestibular Disorders – Tinnitus
Heart Rate and Rhythm Disorders – Arrhythmia, palpitation, tachycardia
Liver and Biliary System – Hepatic function abnormal
Metabolic and Nutritional Disorders – Weight decrease
Psychiatric Disorders – Amnesia, depersonalization, depression, drug abuse, emotional lability, hallucination, impotence, paroniria, abnormal thinking
Red Blood Cell Disorders – Anemia
Respiratory System – Dyspnea
Urinary System – Albuminuria, micturition disorder, oliguria, urinary retention
Vision Disorders – Abnormal vision
Other clinically significant adverse experiences previously reported with tramadol hydrochloride
Other events which have been reported with the use of tramadol products and for which a causal association has not been determined include: vasodilation, orthostatic hypotension, myocardial ischemia, pulmonary edema, allergic reactions (including anaphylaxis and urticaria, Stevens-Johnson syndrome/TENS), cognitive dysfunction, difficulty concentrating, depression, suicidal tendency, hepatitis, liver failure, and gastrointestinal bleeding. Reported laboratory abnormalities included elevated creatinine and liver function tests. Serotonin syndrome (whose symptoms may include mental status change, hyperreflexia, fever, shivering, tremor, agitation, diaphoresis, seizures, and coma) has been reported with tramadol when used concomitantly with other serotonergic agents such as SSRIs and MAOIs.
Other clinically significant adverse experiences previously reported with acetaminophen
Allergic reactions (primarily skin rash) or reports of hypersensitivity secondary to acetaminophen are rare and generally controlled by discontinuation of the drug and, when necessary, symptomatic treatment.
Drug Abuse and Dependence
Abuse
Tramadol has mu-opioid agonist activity. Ultracet®, a tramadol-containing product, can be abused and may be subject to criminal diversion.
Addiction is a primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. Drug addiction is characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, use for non-medical purposes, continued use despite harm or risk of harm, and craving. Drug addiction is a treatable disease, utilizing a multidisciplinary approach, but relapse is common.
"Drug-seeking" behavior is very common in addicts and drug abusers. Drug-seeking tactics include emergency calls or visits near the end of office hours, refusal to undergo appropriate examination, testing or referral, repeated "loss" of prescriptions, tampering with prescriptions, and reluctance to provide prior medical records or contact information for other treating physician(s). "Doctor shopping" to obtain additional prescriptions is common among drug abusers and people suffering from untreated addiction.
Abuse and addiction are separate and distinct from physical dependence and tolerance. Physicians should be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of Ultracet® can occur in the absence of true addiction and is characterized by misuse for non-medical purposes, often in combination with other psychoactive substances.
Concerns about abuse and addiction should not prevent the proper management of pain. However, all patients treated with opioids require careful monitoring for signs of abuse and addiction, because use of opioid analgesic products carries the risk of addiction even under appropriate medical use.
Proper assessment of the patient and periodic re-evaluation of therapy are appropriate measures that help to limit the potential abuse of this product.
Ultracet® is intended for oral use only.
Dependence
Tolerance is the need for increasing doses of drugs to maintain a defined effect such as analgesia (in the absence of disease progression or other external factors). Physical dependence is manifested by withdrawal symptoms after abrupt discontinuation of a drug or upon administration of an antagonist (see also WARNINGS, Withdrawal).
The opioid abstinence or withdrawal syndrome is characterized by some or all of the following: restlessness, lacrimation, rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other 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.
Generally, tolerance and/or withdrawal are more likely to occur the longer a patient is on continuous therapy with Ultracet®.
