الفهرس 
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Abstract
Tramadol is an opioid pain medication used to treat moderate to severe pain. It acts as an agonist on μ-opioid receptors as well as on the noradrenergic and serotonergic systems. Opioid receptors not only present at known parts of the central nervous system but also can be found in the gastrointestinal plexus, vas deference, adrenal medulla, heart & placenta. Tramadol has non opioid action as well. The non opioid action of tramadol causes inhibition of the neuronal reuptake of these neurotransmitters leading to inhibition of pain transmission.
Tramadol is rapidly absorbed orally and it has extensive tissue distribution. The bioavailability of tramadol is 70%. The complete absorption of tramadol takes place in the upper part of the small intestine. Tramadol metabolism occurs in liver by the cytochrome P450 enzyme system and its by-products are excreted unchanged through the kidneys.
Being an opioid, tramadol carries all the possible risks known from other opiates. Long-term use of high doses of tramadol causes physical dependence and withdrawal syndrome.
Several reports suggest that chronic opioid therapy may result in clinically significant hypogonadism and sexual dysfunction. The hormonal effects of opioid usage affect both men and women.