Diphenhydramine (topical)

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients  
• Hypersensitivity to benzoates
• Application to mucous membranes
• Eczematous skin conditions
• Application to broken or denuded skin
• Acute vesicular dermatoses
• Acute exudative dermatoses
• Coadministration with other diphenhydramine containing agents

Cautions 

• Pregnancy 
• Breastfeeding
• Application to large body surface areas
• Prolonged use

Pregnancy

• Caution 
• Following topical administration to large areas of the body, diphenhydramine can be measurable in the blood  
• Diphenhydramine applied topically should only be used in pregnancy when anticipated benefits exceed the risks

Breastfeeding

• Caution 
• Diphenhydramine is present in breast milk when administered orally
• Following topical administration to large areas of the body, diphenhydramine can be measurable in the blood  

Renal impairment

• No dose adjustment recommended

Hepatic impairment

• No dose adjustment recommended

Elderly

• No dose adjustment recommended

Porphyria Information

• Not yet classified (NC)

Skin and Subcutaneous Tissue Disorders

• Sensitisation
• Photosensitivity
• Eczematous reactions

None known

In conditions induced by allergic stimuli, externally applied diphenhydramine has anti-histaminic activity. Diphenhydramine binds to histamine 1-receptor sites in competition with free histamine. This reduces capillary permeability, thereby improving allergy symptoms.