What can I give a patient for itching after receiving Benadryl (diphenhydramine)?

Management of Pruritus After Diphenhydramine Administration

For a patient with persistent itching after receiving Benadryl (diphenhydramine) one hour ago, hydroxyzine is the most appropriate next-line antihistamine treatment, or alternatively, topical hydrocortisone can be applied to affected areas up to 3-4 times daily. 1, 2, 3

Alternative Antihistamine Options

When diphenhydramine has failed to control pruritus, consider the following options:

First-line alternatives:

• Hydroxyzine: 25-50mg orally (preferred for its stronger antipruritic effect)
  • Particularly effective for nighttime pruritus due to its sedative properties 2
  • Note: Has additive sedative effects with recently administered diphenhydramine

Second-line alternatives:

• H1 antihistamine options:

  • Non-sedating options: Cetirizine 10mg, loratadine 10mg, or fexofenadine 180mg 1
  • These may be preferable for daytime use to avoid excessive sedation

• H2 antagonists (can be added to H1 antagonists for synergistic effect):

  • Famotidine or cimetidine 1, 4
  • Combination of H1 and H2 antagonists may be more effective than either alone

Topical Treatment Options

Topical treatments can be used concurrently with oral medications:

• Hydrocortisone cream 1%: Apply to affected areas 3-4 times daily 3

  • Safe and effective for localized pruritus
  • Avoid use on face, genitals, or broken skin unless specifically directed

• Pramoxine-containing products (1%):

  • Provides rapid onset of relief (within 2 minutes) 5
  • Can be used alongside antihistamines

• Menthol-containing preparations:

  • Provides cooling sensation that can help relieve itching 1

Special Considerations

For severe or refractory pruritus:

• Ondansetron: Consider as a rescue medication for persistent pruritus, particularly if opioid-induced 1

Avoid:

• Topical diphenhydramine: Risk of contact dermatitis and potential systemic absorption 6, 7
• Topical calamine lotion: Not recommended for generalized pruritus of unknown origin 1
• Crotamiton cream: Not recommended due to lack of efficacy 1

Pruritus in Specific Conditions

For opioid-induced pruritus:

• Consider nalbuphine or carefully titrated naloxone if pruritus is clearly opioid-related 1
• Ondansetron may be particularly helpful 1

For uremic pruritus:

• Gabapentin may be considered 1
• Broadband UVB phototherapy is effective for many patients 1

For cholestatic pruritus:

• Rifampicin is first-line treatment 1
• Avoid gabapentin in hepatic pruritus 1

Important Cautions

• Monitor for excessive sedation when combining multiple sedating antihistamines
• Elderly patients are more sensitive to anticholinergic effects and sedation from antihistamines 2
• Consider the timing of administration - sedating antihistamines are best given in the evening

By following this algorithmic approach, you can effectively manage pruritus that has not responded to initial diphenhydramine treatment while minimizing adverse effects.