What are the typical dosing regimens for acne treatments, including topical retinoids (e.g. adapalene, tretinoin), benzoyl peroxide, oral antibiotics (e.g. doxycycline, minocycline), and oral isotretinoin?

Acne Treatment Dosing

For mild acne, start with adapalene 0.1-0.3% gel or tretinoin 0.025-0.1% cream/gel once nightly plus benzoyl peroxide 2.5-5% once daily; for moderate-to-severe inflammatory acne, add doxycycline 100 mg once daily or minocycline 100 mg once daily (limit to 3-4 months maximum), and for severe recalcitrant acne, use isotretinoin 0.5 mg/kg/day for month one, then increase to 1.0 mg/kg/day targeting a cumulative dose of 120-150 mg/kg. 1, 2

Topical Retinoid Dosing

Tretinoin:

• Apply 0.025%, 0.05%, or 0.1% cream or gel once nightly to completely dry skin (wait 20-30 minutes after washing) 1, 3
• Start with lower concentrations (0.025%) in sensitive skin, then titrate up as tolerated 1
• Evening application is required due to photolability; avoid concurrent benzoyl peroxide application with standard tretinoin formulations (microsphere formulations lack this restriction) 1, 3

Adapalene:

• Apply 0.1% or 0.3% gel once nightly 1, 4
• 0.1% gel is available over-the-counter; 0.3% requires prescription 4
• More photostable than tretinoin and can be used with benzoyl peroxide 1

Tazarotene:

• Apply 0.05% or 0.1% cream, gel, or foam once nightly 1, 4
• Most potent topical retinoid but also most irritating 1

Benzoyl Peroxide Dosing

• Apply 2.5-5% gel, cream, or wash once or twice daily 1, 4
• Lower concentrations (2.5%) cause less irritation with comparable efficacy to higher concentrations 4
• Can be used morning or evening; if using with tretinoin, apply at different times of day 1
• Always combine with antibiotics (topical or oral) to prevent bacterial resistance 1, 4

Topical Antibiotic Dosing

Clindamycin:

• Apply 1% gel, lotion, or solution twice daily, always combined with benzoyl peroxide 1, 4
• Fixed-combination products (clindamycin 1%/BP 5% or 3.75%) applied once or twice daily enhance compliance 1, 4

Erythromycin:

• Apply 2-3% gel or solution twice daily, always combined with benzoyl peroxide 1, 4
• Fixed-combination (erythromycin 3%/BP 5%) applied twice daily 1, 4

Critical caveat: Never use topical antibiotics as monotherapy—this rapidly induces bacterial resistance 1, 4

Oral Antibiotic Dosing

Doxycycline (strongly recommended):

• Standard dosing: 100 mg once or twice daily with food 1, 4
• Subantimicrobial dosing: 40 mg once daily (modified-release formulation) for moderate inflammatory acne 4
• Maximum duration: 3-4 months to minimize resistance development 1, 4

Minocycline (conditionally recommended):

• 100 mg once or twice daily 1, 4
• More lipophilic than doxycycline, potentially better tissue penetration 1
• Maximum duration: 3-4 months 1, 4

Essential practice point: Always prescribe oral antibiotics with topical retinoid plus benzoyl peroxide (triple therapy) for moderate-to-severe acne 1, 4

Oral Isotretinoin Dosing

Severe acne dosing:

• Month 1: Start at 0.5 mg/kg/day with food (high-fat meal doubles absorption) 1, 2
• Month 2 onward: Increase to 1.0 mg/kg/day as tolerated 1
• Target cumulative dose: 120-150 mg/kg over treatment course 1
• Extremely severe cases may require lower starting doses (0.1-0.25 mg/kg/day) with or without concurrent oral corticosteroids 1

Moderate treatment-resistant acne dosing:

• 0.25-0.4 mg/kg/day (low-dose regimen) 1
• Equally effective as standard dosing for moderate acne with fewer side effects and equal relapse rates 1
• Cumulative dose targets are less critical for moderate acne compared to severe acne 1

Dosing considerations:

• Always take with food to optimize absorption (bioavailability more than doubles with high-fat meal) 2
• Doses above 150 mg/kg cumulative may not provide additional benefit 1
• Intermittent dosing is not recommended due to higher relapse rates 1

Hormonal Therapy Dosing (Female Patients)

Combined oral contraceptives:

• Standard contraceptive dosing per product labeling 1, 4
• Conditionally recommended for acne with moderate certainty evidence 1

Spironolactone:

• Typical dosing: 25-200 mg daily (most commonly 50-100 mg daily) 1, 4
• Potassium monitoring not needed in healthy patients without risk factors for hyperkalemia 1
• Particularly useful for hormonal acne patterns or antibiotic-intolerant patients 4

Additional Topical Agents

Azelaic acid:

• Apply 15-20% gel or cream twice daily 1, 4
• Particularly useful for post-inflammatory hyperpigmentation 4

Clascoterone:

• Apply 1% cream twice daily 1, 4
• Topical antiandrogen conditionally recommended due to high cost 1

Salicylic acid:

• Over-the-counter 0.5-2% formulations once or twice daily 1, 4
• Limited evidence for efficacy; primarily used as adjunctive therapy 1

Topical dapsone:

• Apply 5% gel once or twice daily 1, 4
• Particularly effective for inflammatory acne in adult females 1, 4
• No G6PD testing required for topical formulation 4

Maintenance Therapy Dosing

• Continue topical retinoid (adapalene 0.1-0.3% or tretinoin 0.025-0.1%) once nightly indefinitely after clearance 1, 4
• Add benzoyl peroxide 2.5-5% once daily if needed for more severe baseline disease 4
• Maintenance prevents microcomedone formation and reduces relapse rates 1, 4

Critical Dosing Pitfalls to Avoid

• Never apply tretinoin to wet skin—wait 20-30 minutes after washing for complete drying to minimize irritation 3
• Never exceed 3-4 months of oral antibiotics without re-evaluation and transition to alternative therapy 1, 4
• Never use antibiotics without concurrent benzoyl peroxide—resistance develops rapidly 1, 4
• Never start isotretinoin at full dose in extremely severe acne—risk of acne fulminans-like flare requires lower starting doses (0.1-0.25 mg/kg/day) with possible oral corticosteroid coverage 1
• Never take isotretinoin on empty stomach—absorption is significantly reduced without food 2