How should I write a prescription for lidocaine 5% topical patches (5 cm × 5 cm) for pain control?

How to Write a Prescription for Lidocaine 5% Patches

Prescribe lidocaine 5% patches with instructions to apply up to 3 patches to the painful area for 12 hours daily, followed by a mandatory 12-hour patch-free interval, with a quantity of 90 patches per month (30-day supply). 1

Prescription Format

Write the prescription as follows:

Medication: Lidocaine 5% topical patch (700 mg per patch, 10 cm × 14 cm)

Quantity: 90 patches (30-day supply)

Directions: Apply up to 3 patches to the painful area once daily. Leave on for 12 hours, then remove for 12 hours. Apply to intact skin only.

Refills: As appropriate for the clinical situation

1, 2

Key Prescribing Instructions to Include

Application Protocol

• Maximum of 3-4 patches applied simultaneously to cover the painful area 1, 2, 3
• 12 hours on, 12 hours off schedule is mandatory to prevent cumulative toxicity and skin sensitization 1, 2
• Apply to intact skin only over the most painful regions—never on broken or inflamed skin, as this dramatically increases systemic absorption 1, 2, 3

Quantity Calculation

• If using 3 patches daily with the 12-hour on/off schedule, the patient needs 90 patches per 30-day supply 1
• The 5% prescription strength is preferred over the 4% over-the-counter formulation for neuropathic pain 1

Critical Safety Parameters to Communicate

Absolute Contraindications

• Advanced liver failure/hepatic dysfunction—hepatic impairment reduces lidocaine clearance by 60%, creating toxicity risk even with topical application 1, 2
• Known hypersensitivity to amide-type local anesthetics 1, 2
• Application to broken or inflamed skin 1, 2, 3

Important Precautions

• Avoid excessive heat application over patch areas, as this increases systemic absorption 1, 2, 3
• Do not use within 4 hours of other local anesthetic interventions to prevent cumulative toxicity 1, 2
• Remove patches before starting intravenous lidocaine therapy if applicable 2, 3

Signs of Systemic Toxicity to Monitor

Instruct patients to watch for and report:

• Dizziness or confusion 1, 2, 3
• Drowsiness or altered consciousness 1, 2
• Bradycardia 1, 2
• Muscle twitching 1, 2, 3
• Perioral numbness 2

Though these are uncommon with proper topical use, they warrant immediate discontinuation 1, 4

Special Population Considerations

Renal Impairment

• No dose adjustment required for renal impairment with lidocaine patches, unlike gabapentin or pregabalin which require dose adjustment 1, 2

Elderly Patients

• No dose adjustment needed—the patch remains safe in elderly patients due to minimal systemic absorption 2
• Elderly patients are at higher risk with systemic lidocaine but not with topical patches 2

Hepatic Impairment

• Contraindicated in advanced liver failure—do not prescribe 1, 2

Expected Efficacy and Trial Duration

Trial Period

• Allow at least 3-4 weeks for an adequate therapeutic trial before determining efficacy 1, 3
• For postherpetic neuralgia specifically, approximately 60% of patients achieve moderate to complete pain relief with proper application 3

When to Add Combination Therapy

• If inadequate relief after 3-4 weeks, consider adding gabapentin (starting 100-300 mg nightly, titrating to 900-3600 mg daily in divided doses) or pregabalin (starting 50 mg three times daily, titrating to 100 mg three times daily) for the neuropathic component 5, 1, 3
• Lidocaine patches may be used as coanalgesic in combination with opioids, antidepressants, and/or anticonvulsants 5, 2

Common Pitfalls to Avoid

• Do not prescribe for widespread pain distribution—lidocaine patches are most effective for well-localized, superficial neuropathic pain rather than deep radicular pain 1, 3
• Do not use for wound care—manufacturers explicitly warn against application to open wounds 2
• Do not exceed 12 hours of continuous application—the patch-free period is essential to minimize skin irritation and prevent toxicity 1, 2, 3
• Do not assume pacemakers are a contraindication—this is only relevant for intravenous lidocaine, not topical patches 2

Pharmacokinetics and Safety Profile

• Minimal systemic absorption occurs even with four patches applied over 24 hours, with highest measured blood levels at only 0.1 micrograms/ml 3, 4
• Adverse events are rare and mild, mostly limited to skin redness or irritation at the application site 6, 7
• No clinically significant drug-drug interactions with anticoagulants (warfarin or DOACs) due to minimal systemic absorption 2