Tramadol

Tramadol (marketed as Ultram, and as generics) is an opioid pain medication used to treat moderate to moderately severe pain. When taken as an immediate-release oral formulation, the onset of pain relief usually occurs within about an hour. It has two different mechanisms. First, it binds to the μ-opioid receptor. Second, it inhibits the reuptake of serotonin and norepinephrine.

Serious side effects may include seizures, increased risk of serotonin syndrome, decreased alertness, and drug addiction. The risk of serotonin syndrome appears to be low. Common side effects include: constipation, itchiness and nausea, among others. A change in dosage may be recommended in those with kidney or liver problems. Its use is not recommended in women who are breastfeeding or those who are at risk of suicide.

Tramadol is marketed as a racemic mixture of both R- and S-stereoisomers. This is because the two isomers complement each other's analgesic activity. It is often combined with paracetamol (acetaminophen) as this is known to improve the efficacy of tramadol in relieving pain. Tramadol is metabolised to O-desmethyltramadol, which is a more potent opioid. It is of the benzenoid class.