Oral thrush (oral candidiasis) is a fungal infection of the mouth caused by overgrowth of Candida species, most commonly Candida albicans. It presents as white patches on the tongue, inner cheeks and roof of the mouth that can be scraped off to reveal raw, red tissue underneath.
While oral thrush can affect anyone, it is particularly common in three groups that pharmacists encounter regularly: denture wearers, patients using inhaled corticosteroids and immunocompromised individuals.
Who gets oral thrush?
| Risk group | Why they are susceptible | Pharmacy action |
|---|---|---|
| Denture wearers | Dentures create a warm, moist environment favouring Candida growth | Denture hygiene advice |
| Inhaled corticosteroid users (asthma/COPD) | Steroid deposits in the mouth suppress local immune response | Inhaler technique check, spacer use, mouth rinsing |
| Babies (under 12 months) | Immature immune system | Common and usually self-limiting |
| Older adults | Age-related immune decline, dry mouth from medications | Assess medication list for contributing drugs |
| Antibiotic users | Broad-spectrum antibiotics disrupt normal oral flora | Advise on signs during/after antibiotic course |
| Immunocompromised patients | HIV, chemotherapy, high-dose systemic steroids | Refer if first presentation or recurrent |
OTC treatment: miconazole oral gel
The first-line pharmacy treatment for oral thrush in adults and children over 4 months is miconazole oral gel (Daktarin Oral Gel), available without prescription for adults and children aged 4 months and over.
How to advise patients:
- Apply a small amount (approximately half a 5ml spoonful for adults) to the affected area four times daily
- Hold the gel in the mouth for as long as possible before swallowing
- Apply after meals and at bedtime
- Continue treatment for 7 days after symptoms resolve to prevent recurrence
- Total treatment course is typically 7–14 days
Key drug interaction: miconazole — even as an oral gel — interacts with warfarin. It inhibits CYP2C9, potentially increasing INR and bleeding risk. Pharmacists must check whether the patient takes warfarin or other coumarin anticoagulants before supplying. If so, refer to GP.
Prescription treatments
For cases where miconazole is contraindicated or has failed, GPs may prescribe:
- Nystatin oral suspension: swish and hold in the mouth four times daily. Less effective than miconazole in clinical trials but safer in patients on warfarin
- Fluconazole capsules: 50mg daily for 7–14 days for resistant or severe cases
Prevention: the pharmacy conversation
Much of the pharmacy value in oral thrush lies in prevention advice:
For inhaler users
Oral thrush is a well-recognised side effect of inhaled corticosteroids (beclometasone, budesonide, fluticasone). PharmSee's inhaler technique review guide covers this in detail, but the key prevention steps are:
- Rinse the mouth thoroughly with water after every inhaler dose
- Use a spacer device with metered-dose inhalers — this reduces oropharyngeal deposition
- Review whether the steroid dose could be stepped down (in consultation with the prescriber)
For denture wearers
- Remove dentures at night and soak in denture cleanser
- Brush dentures daily with a soft brush (not toothpaste, which is too abrasive)
- Ensure dentures fit properly — ill-fitting dentures create friction points where Candida thrives
- Clean the palate and gums with a soft brush before replacing dentures
For patients on antibiotics
Broad-spectrum antibiotics (amoxicillin, co-amoxiclav, doxycycline) disrupt the normal oral microbiome, creating opportunity for Candida overgrowth. Pharmacists should mention this risk when counselling patients on antibiotic courses and advise them to return if white patches or soreness develop.
When to refer
Pharmacists should refer the following patients rather than supplying OTC treatment:
- First presentation in an immunocompromised patient (HIV, chemotherapy, systemic steroids >10mg prednisolone equivalent daily)
- Recurrent oral thrush (3+ episodes in 12 months) — may indicate undiagnosed diabetes, immunodeficiency or medication-related cause
- Thrush that does not respond to 14 days of miconazole — possible resistant Candida species
- Angular cheilitis (cracking at the corners of the mouth) without oral patches — may be bacterial rather than fungal
- Difficulty swallowing alongside oral thrush — suggests oesophageal extension, requiring systemic treatment
- Infants under 4 months — miconazole oral gel is not licensed for this age group
Community pharmacists across England's 13,147 registered branches are often the first point of contact for oral thrush. For patients seeking advice on inhaler technique, medication reviews or pharmacy services in their area, PharmSee's pharmacy finder provides comprehensive coverage of every registered community pharmacy.
Sources
- NICE Clinical Knowledge Summary, Oral candidiasis (2024)
- BNF, Miconazole — oral infections
- GPhC, Standards for pharmacy professionals
- PharmSee pharmacy register data, April 2026 (13,147 registered community pharmacies in England)