What is tramadol and acetaminophen, and how does it work (mechanism of action)?

Ultracet is a combination of two drugs, tramadol (Ultram) and acetaminophen (Tylenol) that is used to relieve moderate, acute pain such as pain following dental or surgical procedures. Tramadol and acetaminophen each relieve pain, but they do so by different mechanisms. Tramadol achieves pain relief in two ways. It binds to the -opioid receptor on nerves (the same mechanism that is responsible for the effectives of narcotics, such as morphine), and it also inhibits the reuptake by nerves of two neurotransmitters, serotonin and norepinephrine, that the nerves use to communicate with one another. This inhibition may lead to reduced transmission of pain signals from nerve to nerve in the spinal cord and brain. Acetaminophen achieves pain relief in the spinal cord and brain by increasing the threshold to pain, that is, by increasing the strength of the painful stimulus that is necessary in order to give rise to the sensation of pain. It does this by inhibiting an enzyme that makes prostaglandins. Ultracet was approved by the FDA in 2001.

What brand names are available for tramadol and acetaminophen?


Do I need a prescription for tramadol and acetaminophen?


What are the side effects of tramadol and acetaminophen?

Ultracet usually is well-tolerated. The most common side effects are:

Because tramadol is chemically related to the narcotic class of drugs such as morphine and hydrocodone (Vicodin ES, Anexsia, Lorcet, Lorcet Plus, Norco), it can cause psychological or physical dependence. Some patients who received tramadol have reported seizures.

Abrupt withdrawal of tramadol may result in the following side effects:

An overdose of acetaminophen can result in severe liver damage.


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What is the dosage for tramadol and acetaminophen?

The usual dose of Ultracet is two tablets every four to six hours as needed for the relief of pain. Patients should not take more than two tablets at a time nor more than 8 tablets per day.

Which drugs or supplements interact with tramadol and acetaminophen?

Carbamazepine (Tegretol) or rifampin can increase the rate of metabolic breakdown of tramadol, thus making tramadol less effective. Concomitant administration of quinidine, fluoxetine (Prozac), paroxetine (Paxil) and amitriptyline (Elavil, Endep), ketoconazole (Nizoral, Extina, Xolegel, Kuric), or erythromycin may reduce elimination of tramadol, increasing the risk for serious side effects from tramadol.

Combining tramadol with monoamine oxidase inhibitors (for example, Parnate), selective serotonin inhibitors (SSRIs, for example, fluoxetine [Prozac]), linezolid (Zyvox), St. John's wort, triptans (for example sumatriptan [Imitrex, Alsuma]) may result in severe side effects such as seizures or a condition called serotonin syndrome. Tramadol may increase central nervous system and respiratory depression when combined with alcohol, anesthetics, narcotics, tranquilizers, or sedative hypnotics.

Is tramadol and acetaminophen safe to take if I'm pregnant or breastfeeding?

Safe use during pregnancy has not been established. There have been reports of neonatal seizures, neonatal withdrawal syndrome, fetal death and stillbirth.

Tramadol is excreted in breast milk. Safe use in nursing mothers has not been established.

What else should I know about tramadol and acetaminophen?

What preparations of tramadol and acetaminophen are available?

Tablets: tramadol, 37.5 mg and acetaminophen, 325 mg.

How should I keep tramadol and acetaminophen stored?

Ultracet should be stored at room temperature, between 15 and 30 C (59-86 F). It should be kept out of the reach of children.


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Ultracet is a combination of the drugs tramadol (Ultram) and acetaminophen. Ultracet is prescribed for the short-term relief of moderately to severe acute pain. Side effects, drug interactions, dosing, pregnancy safety, and warnings and precautions should be reviewed prior to taking this medication.

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Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine REEFERENCE:

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