Fentanyl is approximately how many times more potent than morphine?

Fentanyl is approximately how many times more potent than morphine?

• A. 100x more potent than morphine
• B. 10x more potent than morphine
• C. 5x more potent than morphine
• D. 2x more potent than morphine

Answer: (A)

Potency is the amount of drug needed to produce the same effect. Fentanyl achieves analgesia with far smaller doses because it binds the mu-opioid receptor with very high affinity and it is highly lipophilic, so it crosses the blood-brain barrier quickly. Clinically, fentanyl is about 50–100 times more potent than morphine, with the commonly cited figure being around 100x. That’s why small microgram doses of fentanyl (like 50–100 mcg) can yield analgesia comparable to several milligrams of morphine. The other options underestimate how much less drug is needed with fentanyl, which is why they don’t fit the real potency difference.

Potency is the amount of drug needed to produce the same effect. Fentanyl achieves analgesia with far smaller doses because it binds the mu-opioid receptor with very high affinity and it is highly lipophilic, so it crosses the blood-brain barrier quickly. Clinically, fentanyl is about 50–100 times more potent than morphine, with the commonly cited figure being around 100x. That’s why small microgram doses of fentanyl (like 50–100 mcg) can yield analgesia comparable to several milligrams of morphine. The other options underestimate how much less drug is needed with fentanyl, which is why they don’t fit the real potency difference.