Tramadol

Tramadol is a synthetic opioid, used for treating moderate pain. It is sometimes sold under the brand names Ultracet, Ultram, or Tramal. It is not as euphoric as other opioids, but some users report a bit of a speedy effect from use as well.

Dosage

The maximum recommended daily dosage of Tramadol is 400mg (seizure risk at higher doses). First time users should start with a dose of around 100mg. A good first time strategy for Tramadol is to start with 100mg, wait an hour or so, and then redose with another 50 - 100 mg if you are not feeling nauseous.
Some people report that higher doses of Tramadol do not produce a better effect than more normal doses.
Do NOT attempt the "Tramadol shake test". The maximum effects of Tramadol are not seen until two hours after an oral dose is taken, due to the active metabolite. Attempting the shake test to figure out your seizure threshold will likely result in a grand mal seizure. The effects of Tramadol can last quite a while, so re-dosing over time (stacking your doses in this case) is a bad idea unless you want a seizure or are already familiar with this drug and know your limits.

Effects

Tramadol is a prodrug. On its own it is an extremely weak opioid, serotonin releasing agent, and NRI. It breaks down in the body into a stronger opioid that is very mu-selective and a fast acting NRI. It also has some very weak NMDA-type antagonist effects, similar to those caused by DXM.
Tramadol lasts a long time (upwards of 15 hours in some cases). It is also known to have a high of varying nature overtime because of its metabolism into other drugs. It starts out as a stimulant (generally for 2-3 hours after ingestion), and later feels more like a more classic opiate (so plan accordingly). The effects are more variable from person to person than most opiates, with some people finding it very weak and others moderately strong, and some people feeling more of the stimulant effects and others more of the opioid effects.
A very notable combination is Tramadol and Cannabis. When taken in dosages of 100mg+, Tramadol strongly potentiates your weed and gives you a strong body high as well as getting you ripped out of your mind for hours with a unique mental high.

Routes of Administration

Tramadol is most commonly taken orally. Redosing over time instead of taking one large dose increases bioavailability slightly, but may affect euphoria.
Rectal administration is also said to increase bioavailability.
To potentate, Aleve and Benadryl should work fine. Enzyme blockers will probably not be successful due to the prodrug nature of Tramadol. However, it may be possible to block the break down of the metabolites of Tramadol in this way. DXM should not be used.

Health Concerns

High doses of Tramadol are often associated with seizures. Use of stimulants in combination with Tramadol can increase this risk. Tramadol has also been known to contribute to Serotonin Syndrome, so it should not be combined with most anti-depressants like SSRIs and tricyclic anti-depressents, or DXM.
It is recommended by officials to wait at least two weeks after the discontinuation of SSRIs to start taking Tramadol. The waiting period after stopping tricyclic antidepressants is unknown to me, it is my guess that two weeks should be safe as well.
Some users may also experience constipation at large doses. It is also often difficult to urinate on Tramadol.
In clinical trials Tramadol has been shown to be less addictive than other opiates. However it is still tolerance and dependence building with unique SSRI type withdrawal symptoms (electric shock-type feeling) along with more normal opioid withdrawal symptoms.
If you are epileptic, obviously avoid this medicine like the plague.

Serotonin releasing qualities

Because of its serotonin releasing qualities, tramadol could theoretically be used an antidepressant (though this use is not endorsed by health professionals, for obvious reasons). It is argued that those same SRA qualities also increase the severity of the dependence as well as of the withdrawals.

Legality

Tramadol is an unscheduled prescription drug in the United States. On December 5th, 2008, Tramadol was classified as a Schedule IV drug in the state of Kentucky. It remains unscheduled in the rest of the United States, although many states are considering scheduling it as well.