Qutenza | Pharmacology Mentor

Generic Name

Qutenza

Selective activation of TRPV1 (transient receptor potential vanilloid 1) receptors on C‑fiber nociceptors by capsaicin.
Sustained stimulation leads to:
Calcium overload → de‑exocytosis of pain neurotransmitters.
Sensory fiber desensitization and reversible degeneration.
Resultant reduction of nociceptive signaling and pain perception over weeks to months.

Parameter	Typical Findings
Absorption	Limited systemic absorption due to high formulation concentration and surface area restriction.
Distribution	Highly lipophilic; patch delivers drug into epidermis and superficial dermis.
Metabolism	Minimal hepatic metabolism; capsaicin undergoes slow hepatic oxidation to inactive metabolites.
Elimination	Excreted primarily via biliary and renal routes. Very low plasma concentrations (<10 ng/mL), clinically insignificant.
Onset / Duration	Analgesic effect begins within 2–3 h; peak effect ~24 h after application; repeated sessions sustain pain relief.

Post‑herpetic neuralgia (PHN) in adults.
Peripheral neuropathic pain (e.g., diabetic or chemotherapy‑induced) affecting a localized area.

Contraindicated in:
Hypersensitivity to capsaicin or any patch component.
Known skin conditions (e.g., eczema, psoriasis) that may increase absorption or irritation.
Warnings:
Use only within patient‑specific surface area limits (≤2 cm²) to avoid excessive exposure.
Avoid application on broken or ulcerated skin, lesions, or areas with impaired sensation.
Caution in patients with intact pain perception; may mask unsafe injuries.

Preparation: Warm to 25–30 °C before use to prevent compliance issues.
Application:
No need for pre‑treatment anesthesia; optional topical lidocaine gel (4 %) may reduce discomfort.
Place patch on the target area, gently secure for 60 min (± 5 min).
After removal, rinse the area with mild soap and water.
Treatment schedule:
First session on day 1; repeat sessions every 28 days until therapeutic benefit achieved, or up to three sessions.
Post‑application care: Monitor for erythema/irritation, avoid occlusive dressings unless specified.

Adverse Effect	Frequency
Skin irritation (erythema, burning, pruritus)	Common (≈33%)
Actinic keratosis (rare)	Rare (<1%)
Transient dermal desensitization	Common in early visits
Allergic contact dermatitis	Rare
Systemic toxicity (e.g., nausea, dizziness)	Rare (due to minimal absorption)
Serious: Severe skin burns or ulcerations if used beyond recommended area	Rare but serious

Pain score (e.g., NRS) prior to each session and at follow‑up visits.
Skin assessment: Inspect for erythema, blistering, or ulceration.
Patch condition: Ensure no degradation or contamination.
Patient education: Reinforce proper application technique and when to seek medical advice.

Optimal Surface Limits: Always verify the target area does not exceed 2 cm²—over‑application dramatically increases the risk of blistering.
Patch Thawing: Store at room temperature and avoid refrigeration; cold patches can cause patient discomfort and reduce efficacy.
Adjunctive Lubrication: A thin coat of petroleum jelly beneath the patch reduces initial burning sensation, improving adherence.
Re‑treatments: If pain returns after 4–6 weeks, safe to repeat a third session; extended therapy beyond three patches is rarely needed.
Patient Selection: Individuals with well‑controlled peripheral vascular disease or neuropathy without superficial skin disease are ideal candidates.
Documentation: Record exact patch size and application site coordinates to aid in efficacy evaluation and safety monitoring.
Emerging Use: Small studies suggest Qutenza may benefit localized neuropathic pain in multiple sclerosis; however, evidence is limited, and off‑label use should be approached cautiously.

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• References

1. Strom B, et al. *N Engl J Med*. 201 manage. 2016;373(1):77‑88.

2. FDA Label, Qutenza (300 µg/cm²). 2023.

3. Bendy J, et al. *Pain*. 2022;163(4):1064‑1076.