Claim: Constipation may be caused by Tramadol.

Tramadol , sold under the brandname Ultram among others , 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 works by binding to the μ-opioid receptor . Second , it inhibits the reuptake of serotonin and norepinephrine . It is often combined with paracetamol -LRB- acetaminophen -RRB- as this is known to improve the efficacy of tramadol in relieving pain .   Serious side effects may include seizures , increased risk of serotonin syndrome , decreased alertness , and drug addiction , although 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 . It is not recommended in those who are at risk of suicide . While not recommended in women who are breastfeeding , those who take it should not stop breastfeeding .   Tramadol is a synthetic opioid of the benzenoid class -LRB- it contains a benzene ring -RRB- . In the body it is metabolized to O-desmethyltramadol , which is a more potent opioid .   Tramadol was launched and marketed as `` Tramal '' by the German pharmaceutical company Grünenthal GmbH in 1977 in West Germany , and 20 years later it was launched in countries such as the UK , US , and Australia . It is marketed under many brand names worldwide .