Tramadol is a narcotic-like pain reliever used in medicine to treat moderate to severe pain in adults after an operation or a serious injury. It is also used to treat long-standing pain when weaker painkillers no longer work. Tramadol works by blocking pain signals from travelling along the nerves to the brain. It can still be addictive if abused, especially when taken for a long period of time (chronic) or when taken in larger doses (acute) as a narcotic rather than a pain-killer. In this comprehensive histopathological study, the commercial tramadol hydrochloride prescribed in Egypt was used in both forms, as a solution of 100 mg ampoules or as 225 mg tablets. Male adult Wistar rats (Rattus norvegicus) were used as experimental models that were administered tramadol orally and injection for regular durations and calculated dose concentrations. Some reliable histological, histochemical, immunocytochemical and ultrastructural techniques were applied to investigate the experimental manifestations and life-threatening signs/symptoms of tramadol poisoning and to check the traumatic histopathological and biochemical impacts of tramadol abuse in acute administration modality on lungs of rats. Many histopathological lesions e.g., toxicity Lymphocyte infiltration, hemorrhage, necrotic areas, cytoplasmic and membranous degenerations, depletion or increase of some biomolecules, ultrastructure damages and immunocytochemical signs were recorded. These results were described, evaluated and confirmed to a variety of recent studies. It was concluded that, use of tramadol as a pain-killer in medicine or as an abused narcotic among addicts, should be controlled and we are in need for more extensive attention to the clinical and narcotic abuse of tramadol.

Keywords: Tramadol Acute dose, Rats Lungs, Respiration, Toxicity, Histochemical, Immunocytochemical, Ultrastructure.

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