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Qutenza (Capsaicin) - Description and Clinical Pharmacology



Qutenza (capsaicin) 8% patch contains capsaicin in a localized dermal delivery system. The capsaicin in Qutenza is a synthetic equivalent of the naturally occurring compound found in chili peppers. Capsaicin is soluble in alcohol, acetone, and ethyl acetate and very slightly soluble in water.

Qutenza is a single-use patch stored in a foil pouch. Each Qutenza patch is 14 cm x 20 cm (280 cm2) and consists of a polyester backing film coated with a drug-containing silicone adhesive mixture, and covered with a removable polyester release liner.

The backing film is imprinted with "capsaicin 8%". Each Qutenza patch contains a total of 179 mg of capsaicin (8% in adhesive, 80 mg per gram of adhesive) or 640 micrograms (mcg) of capsaicin per square cm of patch.

The empirical formula is C18H27NO3, with a molecular weight of 305.42. The chemical compound capsaicin [(E)-8-methyl-N-vanillyl-6-nonenamide] is an activating ligand for transient receptor potential vanilloid 1 receptor (TRPV1) and it has the following structure:

Structural Formula of Capsaicin

The patch contains the following inactive ingredients: diethylene glycol monoethyl ether, dimethicone, ethyl cellulose, polyester film, silicone adhesive and white ink.

Qutenza is supplied with a Cleansing Gel which is used to remove residual capsaicin from the skin after treatment. Cleansing Gel consists of the following ingredients: butylated hydroxyanisole, carbomer copolymer, edetate disodium, polyethylene glycol, purified water, and sodium hydroxide.


Mechanism of Action

Capsaicin is an agonist for the transient receptor potential vanilloid 1 receptor (TRPV1), which is an ion channel-receptor complex expressed on nociceptive nerve fibers in the skin. Topical administration of capsaicin causes an initial enhanced stimulation of the TRPV1-expressing cutaneous nociceptors that may be associated with painful sensations. This is followed by pain relief thought to be mediated by a reduction in TRPV1-expressing nociceptive nerve endings [see Clinical Pharmacology (12.2)]. Over the course of several months, there may be a gradual re-emergence of painful neuropathy thought to be due to TRPV1 nerve fiber reinnervation of the treated area.


Two studies evaluated the pharmacodynamic effects of Qutenza on sensory function and epidermal nerve fiber (ENF) density in healthy volunteers. Consistent with the known pharmacodynamic effects of capsaicin on TRPV1-expressing nociceptive nerve endings, reduced ENF density and minor changes in cutaneous nociceptive function (heat detection and sharp sensation) were noted one week after exposure to Qutenza. ENF density reduction and sensory changes were fully reversible.


Pharmacokinetic data in humans showed transient, low (< 5 ng/mL) systemic exposure to capsaicin in about one third of PHN patients following 60-minute applications of Qutenza. The highest plasma concentration of capsaicin detected was 4.6 ng/mL and occurred immediately after Qutenza removal. Most quantifiable levels were observed at the time of Qutenza removal and were below the limit of quantitation 3 to 6 hours after Qutenza removal. No detectable levels of metabolites were observed in any subject.


Carcinogenesis, Mutagenesis, Impairment of Fertility


Adequate carcinogenicity studies have not been conducted with Qutenza or capsaicin.


Capsaicin was not mutagenic in the Ames, mouse micronucleus and chromosomal aberration in human peripheral blood lymphocytes assays. As with other catechol-containing compounds (e.g., dopamine), capsaicin showed a weak mutagenic response in the mouse lymphoma assay.

Impairment of Fertility

A fertility and reproductive toxicology study was conducted in rats with exposure to Qutenza patches daily for 3 hours/day beginning 28 days before cohabitation, through cohabitation and continuing through the day before sacrifice (approximately 49 days of treatment). The results revealed a statistically significant reduction in the number and percent of motile sperm. Sperm motility obtained from the vas deferens was reduced in all capsaicin treatment groups (16, 24 and 32 mg capsaicin patch/rat/day). Though a "no effect" level was not determined, dose levels used in the study correspond to a 13- to 28-fold exposure margin over the mean Cmax associated with the maximal human recommended dose. Sperm counts were reduced in the vas deferens or cauda epididymis in the 24 and 32 mg capsaicin patch/rat/day dose groups (79 and 69%, respectively) compared to the placebo patch treated control group; however, these reductions did not adversely affect fertility. As this animal model has a large excess of sperm generating capacity relative to the threshold necessary for fertilization, the lack of an effect on fertility in this species is of unknown significance for human risk assessment.


Postherpetic Neuralgia

The efficacy of Qutenza, was established in two 12-week, double-blind, randomized, dose-controlled, multicenter studies. These studies enrolled patients with postherpetic neuralgia (PHN) persisting for at least 6 months following healing of herpes zoster rash and a baseline score of 3-9 on an 11-point Numerical Pain Rating Scale (NPRS) ranging from 0 (no pain) to 10 (worst possible pain). Qutenza and a control patch were each applied as a single 60-minute application. The control used in these studies looked similar to Qutenza but contained a low concentration of the active ingredient, capsaicin (3.2 mcg/cm2, 0.04% w/w) to retain blinding regarding the known application site reactions of capsaicin (such as burning and erythema). The baseline mean pain scores across the 2 studies was approximately 6.0. Patients who entered the study on stable doses of pain-control medications were required to keep dosing stable throughout the duration of the study. Approximately half of the patients were taking concomitant medications including anticonvulsants, non-SSRI antidepressants, or opioids for their PHN at study entry. Prior to study patch application a topical anesthetic was applied to the treatment area for 60 minutes. Patients were permitted to use local cooling and additional analgesic medications for treatment-related discomfort as needed through Day 5. Patients recorded their pain daily in a diary.

PHN Study 1: In this 12-week study, the Qutenza group demonstrated a greater reduction in pain compared to the Control group during the primary assessment at Week 8. The percent change in average pain from baseline to Week 8 was -18% (±2%) for the low-dose control and -29% (±2%) for Qutenza.

For various degrees of improvement in pain from baseline to study endpoint, Figure 2 shows the fraction of patients achieving that degree of improvement. The figure is cumulative, so that patients whose change from baseline is, for example, 50%, are also included at every level of improvement below 50%. Patients who did not complete the study through Week 12 or who showed no improvement at Week 12 were assigned 0% improvement. Some patients experienced a decrease in pain as early as Week 1, which persisted throughout the study. The proportion of patients experiencing ≥ 30% reduction in pain intensity from baseline for each week through Week 12 is shown in Figure 3.

Patients Achieving Various Percentages of Reduction in Pain Intensity at
Week 12 – Study 1

Weekly Proportion of Patients Achieving ≥ 30% Pain
Intensity Reduction – Study 1*
Weekly Proportion of Patients Achieving ≥ 30% Pain
Intensity Reduction – Study 2*
*The same patients may not have responded at each timepoint.

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