Matrifen (Fentanyl)

Fentanyl, an opioid analgesic, is indicated for conditions that require sustained opioid delivery.

• Severe chronic non‑cancer pain: provides continuous analgesia over several days.
• Cancer‑related pain: maintains steady plasma levels for tumor‑associated pain.
• Breakthrough pain management: used together with short‑acting opioids to control episodic pain spikes.

• Fentanyl binds selectively to μ‑opioid receptors in the central nervous system, activating inhibitory G‑protein pathways that reduce neuronal excitability and decrease the release of excitatory neurotransmitters. This action lowers the perception of pain and produces analgesia while also affecting respiratory drive and gastrointestinal motility.

Fentanyl transdermal therapy can be associated with a range of adverse reactions.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Constipation: reduced bowel movements.
• Somnolence: increased sleepiness.
• Dizziness: feeling light‑headed.
• Application site erythema: redness where the patch is placed.
• Pruritus: itching at the patch site.

Serious or Rare Side Effects

• Respiratory depression: dangerously slow breathing.
• Severe hypotension: marked drop in blood pressure.
• Cardiac arrhythmia: irregular heart rhythm.
• Adrenal insufficiency: inadequate cortisol production.
• Severe skin reactions: Stevens‑Johnson syndrome or necrosis.
• Opioid dependence or withdrawal syndrome upon abrupt discontinuation.

When prescribing or dispensing Matrifen, several safety measures should be observed.

• Assess opioid tolerance: confirm the patient is opioid‑experienced before initiating therapy.
• Rotate application site: change the skin area with each new patch to avoid irritation.
• Monitor respiratory function: especially during the first 24 hours and after dose adjustments.
• Avoid concurrent MAO inhibitors: risk of severe hypertension or serotonin syndrome.
• Educate on disposal: used patches must be folded and placed in a sharps container.
• Store at room temperature: keep in the original pouch, protect from moisture and direct heat.

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

Major Interactions (Avoid)

• Other strong opioids: additive respiratory depression.
• Monoamine oxidase inhibitors (MAOIs): risk of hypertensive crisis.
• Central nervous system depressants (e.g., benzodiazepines): profound sedation and respiratory compromise.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): increase fentanyl plasma levels.
• Alcohol: enhances sedative effects and respiratory depression.
• CYP3A4 inducers (e.g., rifampin, St. John’s wort): may reduce analgesic efficacy.