Tramadol is centrally acting analgesic. The chemical name for tramadol is (±)cis-2-[(dimethylamino)methyl]-1-(3methoxyphenyl) cyclohexanol hydrochloride. Tramadol is white in color with crystalline powder. The drug is soluble in water and ethanol. It acts in brain through which it causes relief in pain.
- Moderate to severe pain
- Post operative pain
- Pain occurring in fibromyalgia
- Potent analgesic
It involves inhibition of reuptake of norepinephrine and serotonin. It acts as µ-opioid receptor agonist which enhances the serotonin release. Tramadol produces inhibitory action on 5-HT2c receptor. This blockage of 5-HT2c receptor causes lowering of seizers threshold. The active metabolite present in tramadol is O-desmethyltramadol, which is a high affinity ligand of the δ- and κ-opioid receptors.
The mean absolute bioavailability of tramadol is about 75%. This concentration reaches in 2-3hrs. Both the enantiomers of tramadol produce dose dependent response. High plasma concentration achieves in two days. Co-administration of food with drug does not affect the rate of absorption.
The volume of distribution of tramadol was 2.6 L/Kg in men and 2.9 L/Kg. 205 of tramadol binds to plasma protein. Saturation of the drug occurs when the administration of the drug is more than the safe dose. The drug is metabolized by enzymes CYP2D6 and CYP3A4 present in liver.
Tramadol metabolites are eliminated through kidneys. The plasma half life of the drug is 6.3±1.4 hrs. On multiple use of the drug the plasma half life of tramadol increases.
- Patients with hypersensitivity to tramadol
- Any allergy with opioids
- Contraindicated in acute intoxication with alcohol, hypnotics, narcotics, centrally acting analgesics.
- CNS and respiratory depression in patients.
- Complicated acute abdominal conditions
- Renal disease
- Hepatic disease
- Prolong half life can cause difficulty in achieving steady state of drug in body.
- Prolong use makes it carcinogen.