Matrifen (Fentanyl)

Fentanyl is an opioid analgesic used for managing severe pain conditions that require continuous opioid delivery.

• Severe chronic pain: provides continuous opioid analgesia for patients with high pain intensity and established opioid tolerance.
• Cancer pain: delivers steady fentanyl levels to alleviate persistent malignant pain in oncology patients.
• Severe chronic non‑cancer pain: offers long‑acting relief for patients with opioid‑tolerant chronic pain conditions.

• Fentanyl binds as a high‑affinity agonist to μ‑opioid receptors in the central nervous system, activating inhibitory G‑protein pathways that reduce neuronal excitability and diminish the perception of pain. This receptor activation leads to decreased release of neurotransmitters such as substance P and glutamate, resulting in potent analgesic effects while also producing typical opioid‑related central effects.

Fentanyl transdermal therapy may cause a range of adverse reactions.

Common Side Effects

• Nausea: mild to moderate feeling of sickness.
• Constipation: reduced bowel motility leading to hard stools.
• Drowsiness or fatigue: increased sleepiness during daily activities.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Sweating: excessive perspiration unrelated to temperature.
• Dry mouth: reduced salivation causing oral discomfort.

Serious or Rare Side Effects

• Respiratory depression: slowed or shallow breathing that can be life‑threatening.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Anaphylaxis or severe skin reactions: sudden allergic response with rash, swelling, or difficulty breathing.
• Opioid dependence or withdrawal: risk of addiction with prolonged use.
• Adrenal insufficiency: impaired cortisol production leading to fatigue and weakness.

When prescribing or using Matrifen, careful assessment and monitoring are essential.

• Assess opioid tolerance: confirm the patient has adequate prior opioid exposure before initiating therapy.
• Monitor respiratory function: watch for signs of respiratory depression, especially during dose adjustments.
• Avoid concomitant MAO inhibitors: risk of severe opioid toxicity and hypertensive crisis.
• Educate on patch disposal: follow local regulations to prevent accidental exposure or misuse.
• Pregnancy and lactation: use only if the potential benefit justifies the potential risk to the fetus or infant.
• Store at room temperature: keep in the original pouch, protect from moisture and heat, store below 25°C.

Fentanyl may interact with other medicines, altering its safety or effectiveness.

Major Interactions (Avoid)

• Concomitant CNS depressants (e.g., benzodiazepines, barbiturates): may cause profound respiratory depression.
• Monoamine oxidase inhibitors (MAOIs): increase risk of severe opioid toxicity.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): elevate fentanyl plasma levels and overdose risk.
• Alcohol: additive central nervous system depression leading to respiratory compromise.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce fentanyl efficacy.
• Other opioids: cumulative opioid effect can increase sedation and respiratory depression.
• Anticholinergic agents: may exacerbate constipation, a common opioid side effect.