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Tramadol
Tramadol is a widely prescribed opioid analgesic used to manage moderate to moderately severe pain. It is unique among opioids due to its dual mechanism of action, combining opioid receptor agonism with serotonin and norepinephrine reuptake inhibition. This article provides a detailed overview of tramadol, referencing authoritative sources such as the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology. We will explore its mechanism of action, uses, dosage, side effects, precautions, drug interactions, and generic names in pharmacy.
Tramadol exerts its analgesic effects through two primary mechanisms:
- Opioid Receptor Agonism:
- Tramadol and its active metabolite (O-desmethyltramadol, M1) bind to mu-opioid receptors in the central nervous system (CNS), inhibiting pain signal transmission (BNF).
- Serotonin and Norepinephrine Reuptake Inhibition:
- Tramadol blocks the reuptake of serotonin and norepinephrine in the CNS, enhancing descending inhibitory pain pathways (Lippincott).
- Weak Kappa and Delta Opioid Receptor Activity:
- Contributes to its analgesic effects but with a lower risk of respiratory depression compared to other opioids (Lange).
Tramadol is indicated for:
- Acute Pain Management:
- Post-operative pain, trauma, or injury.
- Chronic Pain Management:
- Osteoarthritis, neuropathic pain, or cancer-related pain.
- Off-Label Uses:
- Fibromyalgia, restless legs syndrome, and refractory depression (not BNF-approved).
Dosage varies by formulation and patient condition. Always follow the prescribing physician’s instructions.
Adults:
- Immediate-Release (IR): 50–100 mg every 4–6 hours as needed, not exceeding 400 mg/day.
- Extended-Release (ER): 100–300 mg once daily, not exceeding 300 mg/day (BNF).
Elderly or Renal/Hepatic Impairment:
- Reduce dose and frequency (e.g., 50 mg every 12 hours).
Administration Tips:
- Take with or without food, but avoid alcohol to reduce CNS depression.
- Do not crush or chew ER tablets to prevent rapid release and overdose.
Tramadol is generally well-tolerated but may cause:
Common:
- Nausea, vomiting, or constipation.
- Dizziness, drowsiness, or headache.
- Dry mouth or sweating.
Rare but Serious:
- Respiratory Depression: Especially with overdose or in opioid-naive patients.
- Serotonin Syndrome: Agitation, hyperthermia, tachycardia (with serotonergic drugs).
- Seizures: Increased risk in patients with epilepsy or at high doses.
Dependence or Withdrawal: With prolonged use or abrupt discontinuation
Before using tramadol, inform your healthcare provider if you have:
- A history of substance abuse or dependence.
- Epilepsy or seizure disorders.
- Renal or hepatic impairment.
- Respiratory conditions (e.g., asthma, COPD).
- Allergies to tramadol or other opioids.
Special Populations:
- Pregnancy: Avoid use, especially in the third trimester, due to neonatal withdrawal risk (BNF Category: C).
- Breastfeeding: Tramadol and its metabolites may pass into breast milk; avoid or monitor infant closely.
- Elderly: Increased sensitivity to side effects; use lower doses.
Tramadol interacts with several medications:
- CNS Depressants (e.g., alcohol, benzodiazepines):
- Enhanced sedation, respiratory depression, or coma.
- Serotonergic Drugs (e.g., SSRIs, SNRIs, MAOIs):
- Increased risk of serotonin syndrome (Lippincott).
- CYP2D6 Inhibitors (e.g., fluoxetine, paroxetine):
- Reduce conversion to active metabolite (M1), decreasing efficacy (Lange).
- CYP3A4 Inducers (e.g., rifampicin, carbamazepine):
- Lower tramadol levels, reducing pain relief.
- Other Opioids:
- Additive CNS and respiratory depression.
Generic Names in Pharmacy
- Tramadol hydrochloride (active ingredient)
- Common brand names: Ultram®, Zydol®, ConZip®
