Opioid + NRI·Analgesia - Opioids

Tapentadol SR

Severe chronic pain, chronic neuropathic pain (e.g., diabetic neuropathy), severe acute pain

S8Authority requiredPBSOPIOIDPalexia IR, Palexia SR+2

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At a glance

Max Dose

500 mg/day

Half-life

5-6 h

Metabolites

INACTIVE

GI Side Effects

LOWER

Cautions

Avoid / Cautions

Concurrent MAOI use, severe respiratory depression, paralytic ileus. Pregnancy Category C.

Where it stands

Rapid Summary

Overview

Modern, dual-acting centrally acting analgesic. Combines mu-opioid agonism with Noradrenaline Reuptake Inhibition (NRI). Significantly cleaner side effect profile than Tramadol.

Clinical Focus

Tapentadol has zero effect on serotonin, completely eliminating the Serotonin Syndrome risk seen with Tramadol. Extremely effective for neuropathic pain.

Bottom Line

Tapentadol SR is a dual-mechanism opioid (mu-agonist + NRI) for chronic pain with less GI side effects than traditional opioids, but carries full opioid dependence risk and serotonin syndrome potential.

Formulation & Access

Brand Names

Palexia IR, Palexia SR

Oral Routes

Do not crush

IR Tablets (50 mg). Sustained Release Tablets (50, 100, 150, 200, 250 mg). Do not crush SR.

Prescribing & PBS

Authority Required (PBS). Highly Restricted (S8).

Indications & Use

Primary

PBSTGA

Severe chronic pain, chronic neuropathic pain (e.g., diabetic neuropathy), severe acute pain.

Clinical Place

Step 3 on the analgesic ladder. Superb replacement for Oxycodone to vastly reduce constipation/nausea, and superior to Tramadol as it lacks seizure/serotonin risks.

Quick reference

Class & Role

Opioid + NRI — Modern, dual-acting centrally acting analgesic.

Route / Formulation

IR Tablets (50 mg). Sustained Release Tablets (50, 100, 150, 200, 250 mg). Do not crush SR. (Palexia IR, Palexia SR)

Usual Dose & Max

Start PO 50 mg BD (SR tablets). Titrate by 50 mg/day every 3-5 days to target pain relief. Max 500 mg/day.

Key Indication Doses

Chronic / Neuropathic Pain: Start PO 50 mg BD (SR tablets). Titrate by 50 mg/day every 3-5 days to target pain relief. Max 500 mg/day. Acute Severe Pain: PO 50-100 mg q4-6h PRN (IR tablets, max 700mg on day 1 only, then 600mg). Renal Impairment: Avoid if eGFR < 30 (Lack of safety data, though theoretically safer than morphine).

Best Uses

Key Risks

Gastrointestinal: Nausea, vomiting, and constipation are statistically much lower than equivalent doses of Oxycodone or Morphine. Neurological: Dizziness, somnolence. (Lower seizure risk than tramadol). Respiratory: Respiratory depression (though theoretically slightly less than pure mu-agonists like oxycodone).

Key Interactions

Tapentadol does NOT rely on CYP450 enzymes. It is immune to the drug interactions that plague Tramadol and Codeine. Additive sedation with alcohol, benzos, and antipsychotics.

Monitoring

Monitor SpO2 and RR upon initiation. Assess for adequate pain relief. No specific routine laboratory tests required.

Clinical Pearl

Because of the strong noradrenaline reuptake inhibition, Tapentadol is uniquely effective for nerve pain (sciatica, radiculopathy, diabetic neuropathy) where pure opioids like Oxycodone often fail miserably.

Access

Authority requiredPalexia IR, Palexia SR50 mg tablet

Brand: Palexia IR, Palexia SR
PBS status: Authority required
Formulation: IR Tablets (50 mg). Sustained Release Tablets (50, 100, 150, 200, 250 mg). Do not crush SR.

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