<p>Paracetamol has analgesic and antipyretic properties with weak anti-inflammatory activity. Paracetamol (Acetaminophen) is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis. Paracetamol is a para aminophenol derivative, has analgesic and antipyretic properties with weak anti-inflammatory activity. Paracetamol is one of the most widely used, safest and fast acting analgesic. It is well tolerated and free from various side effects of aspirin.<br />
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Tramadol is a centrally acting synthetic opioid analgesic. Although its mode of action is not completely understood, from animal tests, at least two complementary mechanisms appear applicable: binding of parent and M1&nbsp;metabolite to &mu;-opioid receptors and weak inhibition of the reuptake of norepinephrine and serotonin. Opioid activity is due to both low affinity binding of the parent compound and higher affinity binding of the O-demethylated metabolite M1&nbsp;to &mu;-opioid receptors. Tramadol has been shown to inhibit reuptake of norepinephrine and serotonin in vitro, as have some other opioid analgesics.These mechanisms may contribute independently to the overall analgesic profile of tramadol.</p>