Available Fentanyl Transdermal Patch Strengths
The fentanyl transdermal patch is available in seven different delivery-rate strengths: 12,25,37.5,50,62.5,75, and 100 mcg/hr 1.
Standard Strengths
The original four strengths that have been available for decades include:
- 25 mcg/hr (7.8 cm², 2.75 mg fentanyl content)
- 50 mcg/hr (15.6 cm², 5.50 mg fentanyl content)
- 75 mcg/hr (23.4 cm², 8.25 mg fentanyl content)
- 100 mcg/hr (31.3 cm², 11.0 mg fentanyl content)
These four strengths are referenced in the NCCN cancer pain guidelines for opioid conversion calculations 2.
Lower and Intermediate Strengths
Three additional strengths expand dosing flexibility:
12 mcg/hr (3.9 cm², 1.375 mg fentanyl content) - The lowest available strength, particularly beneficial for opioid-naïve patients, elderly patients, or those requiring fine-tuning of analgesia 1
37.5 mcg/hr (11.7 cm², 4.125 mg fentanyl content) - Intermediate strength introduced in 2015 3
62.5 mcg/hr (19.6 cm², 6.875 mg fentanyl content) - Intermediate strength introduced in 2015 3
Clinical Considerations
All patches are designed for 72-hour wear, though some patients may require replacement every 48 hours 2. The amount of fentanyl released per hour is directly proportional to the surface area (25 mcg/hr per 7.8 cm²), and the composition per unit area is identical across all strengths 1.
For doses exceeding 100 mcg/hr, multiple patches should be applied simultaneously 2. Each patch is color-coded with green printing and distinguishable by visual markers - the 12 mcg/hr has a green border, while higher strengths have increasing numbers of green stripes 1.
Important Caveat About Intermediate Strengths
While the 37.5 and 62.5 mcg/hr patches provide more precise dose titration, they typically cost significantly more than the original four strengths 3. In many cases, combining standard-strength patches (e.g., using 25 + 12 mcg/hr patches instead of a single 37.5 mcg/hr patch) may be more cost-effective while achieving the same therapeutic effect.