<unk>  may not provide adequate pain control for individuals with certain genetic variants of CYP2D6 enzymes as they metabolize<unk>  to the inactive molecule. These genetic polymorphisms are not currently routinely tested for in clinical practice. Pregnancy and lactation<unk> 's use in pregnancy is generally avoided, as it may cause some reversible withdrawal effects in the newborn. A small prospective study in France found, while an increased risk of miscarriages existed, no major malformations were reported in the newborn. Its use during lactation is also generally advised against, but a small trial found that infants breastfed by mothers taking<unk>  were exposed to about 2.88% of the dose the mothers were taking. No evidence of this dose harming the newborn was seen. Labor and delivery Its use as an analgesic during labor is not advised due to its long onset of action (1 hour). The ratio of the mean concentration of the drug in the fetus compared to that of the mother when it is given intramuscularly for labor pains has been estimated to be 1:94. Children Its use in children is generally advised against, although it may be done under the supervision of a specialist. On 21 September 2015, the FDA started investigating the safety of<unk>  in use in persons under the age of 17. The investigation was initiated because some of these people have experienced slowed or difficult breathing. The FDA lists age under 12 years old as a contraindication. Elderly The risk of opioid-related adverse effects such as respiratory depression, falls, cognitive impairment and sedation is increased.<unk>  may interact with other medications and increase the risk for adverse events. Liver and kidney failure The drug should be used with caution in those with liver or kidney failure, due to metabolism in the liver (to the active molecule desmetramadol) and elimination by the kidneys.
Tramadol
Tapentadol
Desmetramadol
Hydrocodone
Etodolac
Ketorolac
Oxycodone
Acetylmethadol