Matrifen (Fentanyl)

Fentanyl transdermal patches are used to provide opioid analgesia for persistent pain conditions.

• Chronic cancer pain: delivers continuous opioid relief for patients with ongoing malignant pain.
• Severe chronic non‑cancer pain: supplies steady fentanyl levels for opioid‑tolerant individuals with debilitating non‑cancer pain.
• Opioid‑tolerant patients requiring long‑term analgesia: offers a convenient, non‑oral delivery system for continuous pain control.

• Fentanyl binds to μ‑opioid receptors in the central nervous system, activating inhibitory G‑protein pathways that reduce neuronal excitability and diminish the transmission of nociceptive signals. This receptor agonism leads to potent analgesia by decreasing the perception of pain and altering pain‑modulating pathways.

Fentanyl patches can cause a range of adverse reactions, from mild to life‑threatening.

Common Side Effects

• Nausea: feeling of sickness or urge to vomit.
• Constipation: reduced bowel movements and hard stools.
• Drowsiness: increased sleepiness or fatigue.
• Dry mouth: reduced salivation leading to a parched feeling.

Serious or Rare Side Effects

• Respiratory depression: slowed or shallow breathing that can be fatal.
• Severe hypotension: marked drop in blood pressure causing dizziness or fainting.
• Skin necrosis at the application site: tissue death requiring medical attention.
• Anaphylaxis: severe allergic reaction with rash, swelling, and airway compromise.

Before initiating therapy, clinicians should evaluate patient suitability and implement safety measures.

• Assess opioid tolerance: confirm the patient is opioid‑tolerant before starting a fentanyl patch.
• Monitor respiratory function: watch for signs of respiratory depression, especially after dose adjustments.
• Avoid concurrent CNS depressants: limit use of benzodiazepines, alcohol, or other sedatives.
• Use the lowest effective dose: titrate to achieve pain control while minimizing side effects.
• Educate patient on patch disposal: fold used patch and discard according to local regulations.
• Store at room temperature: keep in the original pouch, protect from moisture and heat, and store away from direct sunlight.

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

Major Interactions (Avoid)

• Benzodiazepines or other CNS depressants: can cause profound respiratory depression.
• Monoamine oxidase inhibitors (MAOIs): increase risk of severe hypotension and serotonin syndrome.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): raise fentanyl plasma levels, heightening toxicity.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce fentanyl concentrations, decreasing analgesia.
• Other opioids: additive sedation and respiratory effects require careful dosing.
• Alcohol and antihistamines: can enhance central nervous system depression and should be used with caution.