Matrifen (Fentanyl)

• Fentanyl, delivered via a transdermal system, is used for managing severe pain conditions that require continuous opioid therapy.
• Severe chronic non‑cancer pain: provides continuous opioid analgesia for patients who need around‑the‑clock pain control.
• Cancer‑related pain: offers sustained relief for individuals with malignant disease experiencing persistent pain.
• End‑of‑life pain management: ensures stable analgesia for terminal patients when oral administration is impractical.

• Fentanyl exerts its analgesic effect by binding with high affinity to the μ‑opioid receptors in the central nervous system. Activation of these G‑protein‑coupled receptors inhibits adenylate cyclase activity, reduces calcium influx, and increases potassium efflux, leading to hyperpolarization of neurons and decreased transmission of nociceptive signals. The transdermal matrix allows slow, steady absorption of fentanyl through the skin, maintaining stable plasma concentrations over several days.

Fentanyl transdermal patches may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Nausea: feeling of sickness or urge to vomit.
• Constipation: reduced bowel movements or hard stools.
• Dizziness: light‑headedness or vertigo.
• Application site erythema: redness or irritation where the patch is applied.

Serious or Rare Side Effects

• Respiratory depression: slowed or shallow breathing that can be life‑threatening.
• Severe hypotension: marked drop in blood pressure.
• Opioid dependence or withdrawal: signs of addiction or withdrawal on discontinuation.

When prescribing Matrifen, clinicians should observe several safety measures.

• Assess respiratory function: evaluate baseline breathing and monitor for depression, especially during initiation or dose changes.
• Evaluate opioid tolerance: confirm patient is opioid‑experienced before prescribing a fentanyl patch.
• Avoid use in acute pain: the patch is not intended for short‑term or breakthrough pain management.
• Concomitant CNS depressants: use caution when combined with benzodiazepines, alcohol, or other sedatives.
• Pregnancy and lactation: avoid unless benefits outweigh risks; limited data on safety.
• Store at room temperature: keep below 25 °C, in the original pouch, protected from moisture and direct sunlight.

Fentanyl may interact with other medicines, requiring careful assessment.

Major Interactions (Avoid)

• CNS depressants (e.g., benzodiazepines, barbiturates): can cause profound respiratory depression.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): increase fentanyl plasma levels and toxicity risk.
• Monoamine oxidase inhibitors (MAOIs): may precipitate severe hypotension or serotonin syndrome.

Moderate Interactions (Monitor Closely):\n- CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce fentanyl effectiveness.

• Other opioids: additive sedation and respiratory effects require dose adjustments.
• Serotonergic agents (e.g., SSRIs, tramadol): monitor for signs of serotonin syndrome.