What is the maximum safe duration for leaving a 20% lidocaine patch in place?

What is the maximum safe duration for leaving a 20% lidocaine patch in place?

• A. 5 minutes
• B. 15 minutes
• C. 30 minutes
• D. 60 minutes

Answer: (B)

The key idea is how long a high-concentration topical lidocaine patch can be worn safely without causing systemic toxicity. Lidocaine is absorbed through the skin, and the amount absorbed depends on concentration, size of patch, duration of wear, and skin condition. With a 20% lidocaine patch, the risk of reaching higher plasma levels rises quickly if the patch is left in place too long, so the safe limit is a short wear time that provides local pain relief but keeps systemic exposure minimal. Fifteen minutes is the recommended maximum to achieve analgesia while keeping the chance of lidocaine-related toxicity low. Leaving it on longer—thirty or sixty minutes—increases absorption and the risk of adverse effects, whereas five minutes may not provide meaningful relief. If longer analgesia is needed, reapply after a suitable interval or consider a different approach.

The key idea is how long a high-concentration topical lidocaine patch can be worn safely without causing systemic toxicity. Lidocaine is absorbed through the skin, and the amount absorbed depends on concentration, size of patch, duration of wear, and skin condition. With a 20% lidocaine patch, the risk of reaching higher plasma levels rises quickly if the patch is left in place too long, so the safe limit is a short wear time that provides local pain relief but keeps systemic exposure minimal. Fifteen minutes is the recommended maximum to achieve analgesia while keeping the chance of lidocaine-related toxicity low. Leaving it on longer—thirty or sixty minutes—increases absorption and the risk of adverse effects, whereas five minutes may not provide meaningful relief. If longer analgesia is needed, reapply after a suitable interval or consider a different approach.