Before that, some US states had already classified tramadol as a Schedule IV controlled substance under their respective state laws.Tramadol is classified in Schedule 4 (prescription only) in Australia, rather than as a Schedule 8 Controlled Drug (Possession without authority illegal) like most other opioids.Effective May 2008, Sweden classified tramadol as a controlled substance in the same category as codeine and dextropropoxyphene, but allows a normal prescription to be used.The UK classified tramadol as a Class C, Schedule 3 controlled drug on 10 June 2014, but exempted it from the safe custody requirement. Misuse
Illicit use of the drug is thought to be a major factor in the success of the Boko Haram terrorist organization. When used at higher doses, the drug "can produce similar effects to heroin." Said one former member, "whenever we took tramadol, nothing mattered to us anymore except what we were sent to do because it made us very high and very bold, it was impossible to go on a mission without taking it." Tramadol is also used as a coping mechanism in the Gaza Strip. It is also abused in the United Kingdom, inspiring the title of the TV show Frankie Boyles Tramadol Nights (2010).From March 2019, the Union Cycliste Internationale (UCI) banned the drug, after riders were using the painkiller to improve their performance.
However, two more recent studies failed to find a releasing effect of tramadol at respective concentrations up to 10 and 30 μM. In addition to serotonergic activity, tramadol is also a norepinephrine reuptake inhibitor. It is not a norepinephrine releasing agent. Tramadol does not inhibit the reuptake or induce the release of dopamine.A positron emission tomography imaging study found that single oral 50-mg and 100-mg doses of tramadol to human volunteers resulted in 34.7% and 50.2% respective mean occupation of the serotonin transporter (SERT) in the thalamus. The estimated median effective dose (ED50) for SERT occupancy hence was 98.1 mg, which was associated with a plasma tramadol level of about 330 ng/ml (1,300 nM). The estimated maximum daily dosage of tramadol of 400 mg (100 mg q.i.d.) would result in as much as 78.7% occupancy of the SERT (in association with a plasma concentration of 1,220 ng/ml or 4,632 nM). This is close to that of SSRIs, which occupy the SERT by 80% or more.Peak plasma concentrations during treatment with clinical dosages of tramadol have generally been found to be in the range of 70 to 592 ng/ml (266–2,250 nM) for tramadol and 55 to 143 ng/ml (221–573 nM) for desmetramadol. The highest levels of tramadol were observed with the maximum oral daily dosage of 400 mg per day divided into one 100-mg dose every 6 hours (i.e., four 100-mg doses evenly spaced out per day). Some accumulation of tramadol occurs with chronic administration; peak plasma levels with the maximum oral daily dosage (100 mg q.i.d.)