What are the available drugs, dosages, and durations for psoriasis management?

Psoriasis Management: Available Drugs, Dosages, and Durations

Topical Therapies for Mild Psoriasis

For mild psoriasis (less than 3% body surface area), start with topical corticosteroids as first-line therapy, with potency selected based on location and severity. 1

Topical Corticosteroid Regimens

• High-potency corticosteroids (Class 1-2) should be applied for up to 4 weeks for initial control, with clobetasol propionate spray 0.05% applied twice daily showing 25% complete clearance at 4 weeks 1, 2
• Combination calcipotriene 0.005%/betamethasone dipropionate 0.064% is the most effective topical regimen, achieving clear or almost clear status in 69-74% of patients at 52 weeks versus 27% with vehicle control 1
• For scalp psoriasis, use calcipotriene foam or calcipotriene/betamethasone dipropionate gel for 4-12 weeks 1
• For facial psoriasis, use topical tacalcitol ointment or calcipotriene combined with hydrocortisone for 8 weeks; avoid high-potency corticosteroids due to skin atrophy risk 1

Corticosteroid-Sparing Strategies

• Weekday/weekend regimen: Apply calcitriol ointment 3 mcg/g twice daily on weekdays and clobetasol propionate spray 0.05% twice daily on weekends for up to 4 weeks to minimize steroid exposure while maintaining efficacy 3
• Vitamin D analogs alone (calcipotriene) require 6-8 weeks for effectiveness 4

Systemic Therapies for Moderate-to-Severe Psoriasis

For moderate-to-severe psoriasis (greater than 3% BSA or significant quality of life impact), methotrexate is the preferred initial systemic therapy. 1

Methotrexate

• Initial dose: 0.2 mg/kg body weight weekly 1
• Maintenance dose: 15 mg weekly initially, with maximum of 25-30 mg weekly 1, 5
• Monitoring: Weekly liver function tests initially, then every 1-2 months once stable; weekly CBC, serum urea, electrolyte, and creatinine concentrations initially 6
• Contraception: Avoid conception during treatment and for at least one menstrual cycle after stopping in women 6
• Critical drug interactions: Avoid alcohol, salicylates, NSAIDs, co-trimoxazole, trimethoprim, probenecid, phenytoin, retinoids, pyrimethamine, and furosemide as they increase methotrexate activity 6
• Major adverse effects: Acute marrow suppression, long-term hepatic fibrosis and cirrhosis risk 6, 7

Cyclosporine

• Dosage: 2.5-5 mg/kg daily 1, 5
• Response time: Approximately 3 weeks, with about 60% improvement even in erythrodermic psoriasis 6, 1
• Monitoring: Blood pressure and serum creatinine every 2 weeks for the first 3 months, then monthly if stable 6, 1
• Dose adjustment: Reduce dose if serum creatinine increases or glomerular filtration rate decreases more than 30% from baseline 6
• Critical drug interactions: Avoid aminoglycosides, amphotericin, trimethoprim, ketoconazole, phenytoin, rifampicin, isoniazid, and NSAIDs 6
• Duration: Safe for up to one year; long-term safety beyond this is not established 6

Acitretin (Retinoid)

• Starting dose: 0.75 mg/kg/day (or 25-50 mg daily) for 2-4 weeks 6, 1
• Maintenance dose: Reduce to 0.5 mg/kg/day and titrate down to lowest effective dose 6
• Response time: As early as 3 weeks, particularly effective for pustular psoriasis 1, 5
• Monitoring: CBC, lipid profile, and liver function tests monthly for the first 3 months 1
• Contraception: Absolute contraception required for at least 1 month before, during, and for at least 2 years after stopping treatment due to high risk of fetal malformation and prolonged storage in the body 6, 1

Alternative Systemic Agents

• Hydroxyurea: Effective for severe psoriasis, safe for up to one year 6
• Azathioprine: About 60% response rate; main side effects are bone marrow toxicity, teratogenicity, and oligospermia 6

Biologic Therapies

For moderate-to-severe psoriasis not responding to traditional systemic agents, biologics such as IL-17 and IL-23 inhibitors demonstrate superior efficacy compared to TNF inhibitors. 1

TNF-α Inhibitors

• Adalimumab: 80 mg week 1, then 40 mg week 2, then 40 mg every 2 weeks; maintenance dose can be 40 mg weekly 6
• Certolizumab: 400 mg (two 200 mg subcutaneous injections) every other week; for patients ≤90 kg, alternative is 400 mg initially, at week 2 and week 4, then 200 mg every other week 6
• Combination with topicals: Adding ultrahigh-potency topical corticosteroids (Class 1) to biologics like etanercept for 12 weeks accelerates clearance 1

IL-12/IL-23 Inhibitors

• Ustekinumab (adults):
  • ≤100 kg: 45 mg subcutaneously initially and at 4 weeks, then every 12 weeks 8
  • >100 kg: 90 mg subcutaneously initially and at 4 weeks, then every 12 weeks 8
• Ustekinumab (pediatric 6-17 years):
  • <60 kg: 0.75 mg/kg initially, at 4 weeks, then every 12 weeks 8
  • 60-100 kg: 45 mg initially, at 4 weeks, then every 12 weeks 8
  • >100 kg: 90 mg initially, at 4 weeks, then every 12 weeks 8

Special Clinical Scenarios

Pustular Psoriasis

Acitretin 25-50 mg daily is first-line therapy for pustular psoriasis, with response as early as 3 weeks. 1, 5

• Methotrexate is especially useful in acute generalized pustular psoriasis 1, 5
• Critical warning: Systemic corticosteroids should be strictly avoided except for three rare specific conditions (persistent uncontrollable erythroderma causing metabolic complications; generalized pustular psoriasis of von Zumbusch type if other drugs contraindicated; hyperacute psoriatic polyarthritis threatening severe irreversible joint damage), as withdrawal precipitates erythrodermic or generalized pustular psoriasis 6, 1

Psoriatic Erythroderma

• Methotrexate and cyclosporine are recommended, with cyclosporine achieving about 60% improvement even in erythrodermic psoriasis 1

Psoriatic Arthritis

• TNF-α inhibitors are first-line biologic therapy 5
• Adalimumab: 45 mg subcutaneously initially and at 4 weeks, then every 12 weeks; for patients >100 kg with co-existent moderate-to-severe plaque psoriasis, use 90 mg 6

Combination Therapy Strategies

• Biologics + topical corticosteroids: Adding Class 1 topical corticosteroids to biologics like etanercept for 12 weeks improves outcomes; in one study, 81% of moderate disease, 79.5% of severe disease, and 58.8% of very severe disease achieved clear or almost clear status 1, 9
• Methotrexate + biologics: Can augment efficacy but requires careful monitoring for additive toxicity 5

Critical Safety Warnings and Monitoring

Absolute Contraindications

• Systemic corticosteroids: Avoid in psoriasis management as they cause disease flare during taper and can precipitate life-threatening erythrodermic or pustular psoriasis 6, 1, 5

Pregnancy Considerations

• Methotrexate: Avoid conception during treatment and for at least one menstrual cycle after stopping 6
• Acitretin: Absolute contraception for at least 1 month before, during, and for at least 2 years after stopping treatment 6, 1

Hepatotoxicity Monitoring

• Methotrexate: Liver biopsy should be considered before starting or continuing; weekly liver function tests initially, then every 1-2 months once stable 6, 1

Nephrotoxicity Monitoring

• Cyclosporine: Monitor serum creatinine and blood pressure every 2 weeks for first 3 months; reduce dose if creatinine increases or GFR decreases >30% from baseline 6, 1, 5