Magic Mouthwash (Duke's Mouthwash)
This compounded oral suspension containing lidocaine viscous 5 mL, nystatin 5 mL, and diphenhydramine elixir 5 mL is commonly referred to as "Magic Mouthwash" or "Duke's Mouthwash" 1.
Composition and Purpose
This is a non-standardized compounded formulation used primarily for symptomatic relief of oral mucositis, particularly chemotherapy-induced oral mucositis (CIOM). The three-component mixture combines:
- Lidocaine viscous (2%): Provides topical anesthesia for pain relief 2
- Nystatin suspension (100,000 U/mL): Antifungal agent to treat or prevent oral candidiasis 3, 4
- Diphenhydramine elixir: Antihistamine with anticholinergic and sedative properties that may provide additional mucosal coating and mild analgesic effects 5, 1
Clinical Context and Evidence
The formulation lacks standardization across institutions. A survey of 40 U.S. institutions found that diphenhydramine, viscous lidocaine, and nystatin were among the top five ingredients used in magic mouthwash preparations, though the exact combinations varied significantly 1. Most institutions administer these preparations every 4-6 hours.
Individual Component Evidence
When used separately for oral conditions:
- Nystatin suspension (100,000 U/mL at 4-6 mL four times daily) is recommended by IDSA guidelines for mild oropharyngeal candidiasis 3
- Viscous lidocaine 2% (15 mL per application) is recommended in U.K. guidelines for oral pain management in conditions like Stevens-Johnson syndrome 2
- Diphenhydramine has documented use as a sedation adjunct in endoscopic procedures at 25-50 mg doses 5
Important Caveats
This is a compounded, non-FDA-approved formulation. The evidence supporting the combined use of these three agents specifically is limited to observational data 1. Each component has individual evidence for oral conditions, but the synergistic benefit of this particular combination has not been rigorously evaluated in controlled trials.
Standardized alternatives exist with stronger evidence. For oropharyngeal candidiasis specifically, IDSA guidelines recommend clotrimazole troches or miconazole buccal tablets as first-line for mild disease, with oral fluconazole for moderate-to-severe disease 3. These have high-quality evidence supporting their use.
The typical administration involves swishing and spitting (or swallowing if esophageal involvement is suspected), though specific instructions vary by institution and clinical indication 1.