Some controversy regarding the abuse potential of tramadol exists. Grünenthal has promoted it as having a lower risk of opioid dependence than traditional opioids, claiming little evidence of such dependence in clinical trials (which is true; Grünenthal never claimed it to be non-addictive). They offer the theory that, since the M1 metabolite is the principal agonist at μ-opioid receptors, the delayed agonist activity reduces abuse liability. The norepinephrine reuptake inhibitor effects may also play a role in reducing dependence.
Rarely, dependence may occur after as little as three months of use at the maximum dose—generally depicted at 400 mg per day. However, both physicians and health authorities generally consider dependence liability relatively low. Thus, tramadol is classified as a Schedule 4 Prescription Only Medicine in Australia, and been rescheduled in Sweden rather than as a Schedule 8 Controlled Drug like opioids.[, unlike opioid analgesics, tramadol is not currently scheduled as a controlled substance by the U.S. Drug Enforcement Administration. However, it is scheduled in certain states.., the prescribing information for Ultram warns that tramadol "may induce psychological and physical dependence of the morphine-type". Using tramadol as recreational drug may also be preferred because it is one of the only opioids that is often not screened for by standard urine drug-tests.
Dependence on tramadol has been reported to be a major social problem in the Gaza Strip. The Hamas government has attempted to cut off supplies of the drug, and in April 2010 burnt 2 million tablets which had been intercepted while being smuggled into the territory.
Because of the possibility of convulsions at high doses for some users, recreational use can be very dangerous.[, via agonism of μ opioid receptors, Tramadol can produce effects similar to those of other opioids (codeine and other weak opioids). Due to tramadol's much lower affinity for this receptor, these are not nearly as intense as with the opiates per se. Tramadol can cause a higher incidence of nausea, dizziness, loss of appetite compared with opiates, which could deter abuse.[ Tramadol can alleviate withdrawal symptoms from opiates, and it is much easier to control its usage than for street drugs.[ It may also have large effect on sleeping patterns and high doses may cause insomnia. (Especially for those on methadone, both for maintenance and recreation. Though there is no scientific proof tramadol lessens effects of opiates or is a mixed agonist-antagonist, some people get the impression it is, while someone else might benefit being prescribed both for pain and breakthrough pain.)
