Tramadol
Mechanism :
Tramadol and its O-desmethyl metabolite (M1) are selective, weak OP3-receptor agonists. Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine and noradrenaline is inhibited. The analgesic properties of Tramadol can be attributed to norepinephrine and serotonin reuptake blockade in the CNS, which inhibits pain transmission in the spinal cord. The (+) enantiomer has higher affinity for the OP3 receptor and preferentially inhibits serotonin uptake and enhances serotonin release. The (-) enantiomer preferentially inhibits norepinephrine reuptake by stimulating alpha(2)-adrenergic receptors.
Indication :
Contraindications :
History of head injury, epilepsy or other seizure disorder; History of drug or alcohol addiction; Metabolic disorder; Using certain medicines to treat migraine; Headaches, muscle spasms, depression, mental illness, or nausea and vomiting; Severe asthma or breathing problems; Blockage in stomach or intestines; Recently used alcohol, sedatives, tranquilizers, or narcotic medications.
Dosing :
12-15 years:
1-2 mg/kg/dose every 6 hours. Max: 100 mg/dose.
16 years and older:
Initial dose: 50 to 100 mg every 4 to 6 hours. Max: 400 mg/day.
Alternatively, for patients not requiring a rapid onset of effect, side effects may be decreased by initiating dosage at 25 mg/day and increasing by 25 mg every 3 days up to 25 mg 4 times a day. Dosage may then be increased by 50 mg every 3 days as tolera
Adverse Effect :
Abdominal fullness, abnormal or decreased touch sensation, blisters under the skin, bloating, blood in the urine, hypertension, blurred vision, change in walking and balance, chest pain or discomfort, chills, convulsions, difficult urination, dizziness or light headedness when getting up from a lying or sitting position, fainting, tachycardia, loss of memory, numbness and tingling of the face, fingers, or toes, pale bluish-coloured or cold hands or feet, recurrent fever, visual and auditory hallucinations, severe cramping, severe nausea, severe redness, swelling, and itching of the skin, jaundice.
Interaction :
Almotriptan: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.
Alvimopan: Increases levels by receptor binding competition. Discontinue opioid administration at least 7 days prior to administrating Alvimopan.
Aminoglutethimide: May decrease the effect of Tramadol by increasing Tramadol metabolism and clearance.
Amiodarone: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance. Amiodarone may decrease the effect of Tramadol by decreasing active metabolite production.
Amitriptyline: Tramadol increases the risk of serotonin syndrome and seizures.
Amoxapine: Tramadol increases the risk of serotonin syndrome and seizures.
Amprenavir: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance.
Aprepitant: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance.
Atazanavir: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance.
Benzphetamine: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.
Bosentan: May decrease the effect of Tramadol by increasing Tramadol metabolism and clearance.
Bromocriptine: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.
Cabergoline: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.
Carbamazepine: May decrease the effect of tramadol by increasing Tramadol metabolism and clearance.
Chloroquine: May decrease the effect of Tramadol by decreasing active metabolite production.
Chlorpromazine: May decrease the effect of Tramadol by decreasing active metabolite production.
Cimetidine: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance. Cimetidine may decrease the effect of Tramadol by decreasing active metabolite production.
Cinacalcet: May decrease the effect of Tramadol by decreasing active metabolite production.
Citalopram: The use of two serotonin modulators, such as citalopram and tramadol, may increase the risk of serotonin syndrome. Consider alternate therapy or monitor for serotonin syndrome during concomitant therapy.
Clarithromycin: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance.
Clomipramine: Tramadol increases the risk of serotonin syndrome and seizures. Clomipramine may decrease the effect of Tramadol by decreasing active metabolite production.
Clotrimazole: May increase Tramadol toxicity by decreasing Tramadol metabolism and clearance.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | 50–100 mg every 8 hours initially and titrate dose as tolerated |
| <10 | 50 mg every 8 hours initially and titrate dose as tolerated |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unknown dialysability. Dose as in GFR<10 mL/min |
| HD | Dialysed. Dose as in GFR<10 mL/ min |
| HDF/High flux | Dialysed. Dose as in GFR<10 mL/ min |
| CAV/VVHD | Dialysed. Dose as in GFR=10– 20 mL/min |
Hepatic Dose :
Mild to moderate hepatic impairment: Dose adjustment guidelines are not available. Dose may need to be reduced.
Severe hepatic impairment: Use is not recommended.