From the Guidelines
Doxepin is effective in treating pruritus, particularly in patients with uraemic pruritus.
Recommended Dosage
The recommended oral dose of doxepin for pruritus relief is 10 mg twice daily 1.
Treatment Duration
The typical treatment duration is not well established, but it is recommended to limit the use of topical doxepin to 8 days 2, 3, 4.
Administration
Topical doxepin, available as a 5% cream, can also be applied 4 times daily for up to 8 days, providing localized relief from itch 2, 3, 4.
Side Effects
Common side effects of doxepin include drowsiness, with one-half of patients reporting this symptom 1.
Key Considerations
- Ensure adequate dialysis and normalize calcium-phosphate balance before using doxepin for uraemic pruritus 1.
- Use emollients to manage xerosis, which may contribute to pruritus 1.
- Consider alternative treatments, such as topical capsaicin or clobetasone butyrate, if doxepin is not effective or tolerated 2, 3, 4.
From the Research
Efficacy of Doxepin for Treating Pruritus
- Doxepin has been shown to be effective in reducing pruritus in patients with atopic dermatitis, with significant relief achieved in 85% of doxepin-treated patients compared to 57% of vehicle-treated patients 5.
- Topical application of doxepin cream has been found to provide significant antipruritic activity with a favorable safety profile, suggesting a role for doxepin cream in the symptomatic treatment of pruritus associated with eczematous dermatitis 6.
- Doxepin has also been effective in treating pruritus in patients with lichen simplex chronicus, nummular eczema, and contact dermatitis, with 60% of doxepin-treated patients experiencing pruritus relief within 24 hours 6.
- In patients with end-stage renal disease undergoing hemodialysis, low-dose doxepin has been shown to be effective in improving pruritus, with complete resolution of pruritus reported in 58.3% of patients and relative improvement observed in 29.2% of patients 7.
Mechanism of Action
- Doxepin's antipruritic effect is thought to be due to its ability to block histamine receptors, as well as its anticholinergic properties, which may influence acetylcholine-induced cutaneous reactions in atopic eczema 8.
- The exact mechanism of doxepin's antipruritic effect is still not fully understood, but it is believed to involve the inhibition of histamine release and the blockade of histamine receptors, as well as the modulation of other neurotransmitters and mediators involved in the itch response.
Safety and Tolerability
- Doxepin has been found to be generally well-tolerated, with the most common adverse effects being localized stinging or burning, drowsiness, and dry mouth 5, 6, 7.
- The safety profile of doxepin is favorable, with no major side effects or sensitization reported in clinical trials 5, 6.
- Low-dose doxepin has been shown to be safe and effective in patients with end-stage renal disease undergoing hemodialysis, with the main adverse effect being temporary drowsiness 7.