A 72-year-old client with chronic stable angina is being ins… | MyMerci
Medical EmergenciesPA
Question
A 72-year-old client with chronic stable angina is being instructed on a nitroglycerin transdermal patch applied each morning. Which instruction is most important to prevent nitrate tolerance?
1"Remove the patch each evening and remain patch-free for 10-12 hours overnight to preserve the medication effectiveness."✓ Correct answer
2"Apply the patch to the same site on the chest daily after washing to promote uniform absorption of the drug."
3"Place the patch over a hairy portion of the chest to help the patch stay in place and increase absorption."
4"If a patch becomes detached, apply two new patches the next morning to replace the missed dose and ensure adequate drug levels."
Explanation
Nitrate tolerance and patch-free interval Continuous exposure to nitrates produces tolerance within 24-48 hours, with loss of antianginal effect. To preserve efficacy, dosing must include a nitrate-free interval of 10-14 hours per 24 hours; for transdermal patches the standard is to apply the patch in the morning and remove it at bedtime. (Patients with predominantly nocturnal angina may invert the schedule.) Other patch teaching: • Rotate sites daily — clean, dry, hairless, non-irritated skin (chest, upper arm, back); avoid scars, cuts, hairy areas. • Wash hands after application; remove old patch before applying new. • Do not cut the patch (alters delivery rate). • Avoid heating pads or hot environment near the patch (accelerates release → severe hypotension). • Skin reactions (redness, itching) — rotate site. • During cardioversion or defibrillation, remove the patch (metallic backing arc/burn). • Same contraindication: PDE5 inhibitor (sildenafil/tadalafil/vardenafil) within 24-48 hours = absolute.
In-depth explanation
Clinical reasoning summary Nitrate tolerance and patch-free interval Continuous exposure to nitrates produces tolerance within 24-48 hours, with loss of antianginal effect. To preserve efficacy, dosing must include a nitrate-free interval of 10-14 hours per 24 hours; for transdermal patches the standard is to apply the patch in the morning and remove it at bedtime. (Patients with predominantly nocturnal angina may invert the schedule.) Other patch teaching: • Rotate sites daily — clean, dry, hairless, non-irritated skin (chest, upper arm, back); avoid scars, cuts, hairy areas. • Wash hands after application; remove old patch before applying new. • Do not cut the patch (alters delivery rate). • Avoid heating pads or hot environment near the patch (accelerates release → severe hypotension). • Skin reactions (redness, itching) — rotate site. • During cardioversion or defibrillation, remove the patch (metallic backing arc/burn). • Same contraindication: PDE5 inhibitor (sildenafil/tadalafil/vardenafil) within 24-48 hours = absolute.