Adverse Events Leading to Discontinuation of Treatment
In the controlled trials, 3% of patients in both the Flector Patch and placebo patch groups discontinued treatment due to an adverse event. The most common adverse events leading to discontinuation were application site reactions, occurring in 2% of both the Flector Patch and placebo patch groups. Application site reactions leading to dropout included pruritus, dermatitis, and burning.
Common Adverse Events
Localized Reactions
Overall, the most common adverse events associated with Flector Patch treatment were skin reactions at the site of treatment.
Table 1 lists all adverse events, regardless of causality, occurring in ≥ 1% of patients in controlled trials of Flector Patch. A majority of patients treated with Flector Patch had adverse events with a maximum intensity of "mild" or "moderate."
Table 1. Common Adverse Events (by body system and preferred term) in ≥1% of Patients treated with Flector Patch or Placebo Patch The table lists adverse events occurring in placebo-treated patients because the placebo-patch was comprised of the same ingredients as Flector Patch except for diclofenac. Adverse events in the placebo group may therefore reflect effects of the non-active ingredients.
| Diclofenac N=572 | Placebo N=564 |
|---|
| N | Percent | N | Percent |
|---|
| Application Site Conditions | 64 | 11 | 70 | 12 |
| Pruritus | 31 | 5 | 44 | 8 |
| Dermatitis | 9 | 2 | 3 | <1 |
| Burning | 2 | <1 | 8 | 1 |
| Other Includes: application site dryness, irritation, erythema, atrophy, discoloration, hyperhidriosis, and vesicles. | 22 | 4 | 15 | 3 |
| Gastrointestinal Disorders | 49 | 9 | 33 | 6 |
| Nausea | 17 | 3 | 11 | 2 |
| Dysgeusia | 10 | 2 | 3 | <1 |
| Dyspepsia | 7 | 1 | 8 | 1 |
| Other Includes: gastritis, vomiting, diarrhea, constipation, upper abdominal pain, and dry mouth. | 15 | 3 | 11 | 2 |
| Nervous System Disorders | 13 | 2 | 18 | 3 |
| Headache | 7 | 1 | 10 | 2 |
| Paresthesia | 6 | 1 | 8 | 1 |
| Somnolence | 4 | 1 | 6 | 1 |
| Other Includes: hypoaesthesia, dizziness, and hyperkinesias. | 4 | 1 | 3 | <1 |
Foreign labeling describes that dermal allergic reactions may occur with Flector Patch treatment. Additionally, the treated area may become irritated or develop itching, erythema, edema, vesicles, or abnormal sensation.
Absorption
Following a single application of the Flector Patch on the upper inner arm, peak plasma concentrations of diclofenac (range 0.7 – 6 ng/mL) were noted between 10 – 20 hours of application. Plasma concentrations of diclofenac in the range of 1.3 – 8.8 ng/mL were noted after five days with twice-a-day Flector Patch application.
Systemic exposure (AUC) and maximum plasma concentrations of diclofenac, after repeated dosing for four days with Flector Patch, were lower (<1%) than after a single oral 50-mg diclofenac sodium tablet.
The pharmacokinetics of Flector Patch has been tested in healthy volunteers at rest or undergoing moderate exercise (cycling 20 min/h for 12 h at a mean HR of 100.3 bpm). No clinically relevant differences in systemic absorption were observed, with peak plasma concentrations in the range of 2.2 – 8.1 ng/mL while resting, and 2.7 – 7.2 ng/mL during exercise.
Distribution
Diclofenac has a very high affinity (>99%) for human serum albumin.
Diclofenac diffuses into and out of the synovial fluid. Diffusion into the joint occurs when plasma levels are higher than those in the synovial fluid, after which the process reverses and synovial fluid levels are higher than plasma levels. It is not known whether diffusion into the joint plays a role in the effectiveness of diclofenac.
Metabolism
Five diclofenac metabolites have been identified in human plasma and urine. The metabolites include 4'-hydroxy-, 5-hydroxy-, 3'-hydroxy-, 4',5-dihydroxy- and 3'-hydroxy-4'-methoxy diclofenac. The major diclofenac metabolite, 4'hydroxy-diclofenac, has very weak pharmacologic activity. The formation of 4'-hydroxy diclofenac is primarily mediated by CPY2C9. Both diclofenac and its oxidative metabolites undergo glucuronidation or sulfation followed by biliary excretion. Acylglucuronidation mediated by UGT2B7 and oxidation mediated by CPY2C8 may also play a role in diclofenac metabolism. CYP3A4 is responsible for the formation of minor metabolites, 5-hydroxy and 3'-hydroxy- diclofenac.
Excretion
The plasma elimination half-life of diclofenac after application of Flector Patch is approximately 12 hours. Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Little or no free unchanged diclofenac is excreted in the urine. Approximately 65% of the dose is excreted in the urine and approximately 35% in the bile as conjugates of unchanged diclofenac plus metabolites.
Distributed by: King Pharmaceuticals Inc.
501 Fifth Street
Bristol TN 37620 USA
Telephone: 1-888-840-8884 www.FlectorPatch.com
Manufactured for: IBSA Institut Biochimique SA, CH-6903 Lugano, Switzerland
Manufactured by: Teikoku Seiyaku Co., Ltd., Sanbonmatsu, Kagawa 769-2695 Japan
FI/165 1086
Ed. VI/2.11
Version February, 2011
Repacked by:
H.J. Harkins Company, Inc.
513 Sandydale Drive
Nipomo, CA 93444
| Distributed by: | King Pharmaceuticals Inc 501 Fifth Street Bristol, TN 37620 USA Telephone: 1-888-840-8884 www.FlectorPatch.com |
Manufactured for: IBSA Institut Biochimique SA, CH-6903 Lugano, Switzerland
Manufactured by: Teikoku Seiyaku Co., Ltd., Sanbonmatsu, Kagawa 769-2695 Japan
FI/165 1086
Ed. VI/2.11
Version February, 2011
Repacked by:
H.J. Harkins Company, Inc.
513 Sandydale Drive
Nipomo, CA 93444