What is the recommended dosing of N-acetylcysteine (NAC) for treating skin picking, also known as dermatillomania?

N-Acetylcysteine Dosing for Skin Picking (Dermatillomania)

The recommended dosing of N-acetylcysteine (NAC) for treating skin picking disorder (dermatillomania) is 1200-3000 mg per day, divided into twice daily doses, with most patients showing optimal response at 1200 mg twice daily (2400 mg total daily dose). 1

Evidence-Based Dosing Regimen

Initial Dosing and Titration

• Start with 600 mg twice daily (1200 mg/day) 2
• After 2-4 weeks, if response is inadequate and side effects are minimal, increase to 1200 mg twice daily (2400 mg/day) 1
• Maximum recommended dose: 3000 mg/day 1

Duration of Treatment

• Minimum treatment duration: 12 weeks to assess efficacy 1
• Significant improvements typically observed within 6-12 weeks 2, 1
• Long-term maintenance therapy may be required as skin picking is often a chronic condition

Efficacy Evidence

NAC has demonstrated significant efficacy for skin picking disorder in randomized controlled trials:

• In a randomized, double-blind trial of 66 adults with skin picking disorder, NAC (1200-3000 mg/day) produced significant improvements compared to placebo over 12 weeks 1
• 47% of participants receiving NAC were rated as "much" or "very much" improved compared to only 19% in the placebo group 1
• NAC works by restoring extracellular glutamate concentration in the nucleus accumbens, which helps reduce compulsive behaviors 1

Special Populations

Children and Adolescents

• Starting dose: 600 mg twice daily 2
• Maximum dose: 1200 mg twice daily 2
• A case report of a 17-year-old with trichotillomania (a related condition) showed dramatic improvement with this dosing regimen 2

Patients with Prader-Willi Syndrome

• Lower starting doses may be considered (450-1200 mg/day) 3
• Efficacy may be more limited in this population, with only modest improvements observed in some studies 4

Monitoring and Side Effects

Common Side Effects

• Generally mild and well-tolerated 5
• Most common: gastrointestinal symptoms (nausea, diarrhea, abdominal discomfort) 5, 1
• These side effects can often be minimized by taking NAC with food

Rare Side Effects

• Severe aggression has been reported in one child 5
• Potential for new onset of skin picking in patients with isolated rectal picking (reported in Prader-Willi syndrome) 4

Monitoring

• Assess clinical response at 4,8, and 12 weeks
• Document improvement using standardized scales when possible (e.g., modified Yale-Brown Obsessive Compulsive Scale) 1
• No specific laboratory monitoring is required for NAC when used for skin picking

Clinical Pearls

• NAC is available over-the-counter as a dietary supplement 2
• Quality and potency may vary between brands
• NAC has a sulfur odor that some patients find unpleasant
• Taking with food can improve tolerability
• Consider NAC particularly for patients who have failed first-line treatments like selective serotonin reuptake inhibitors (SSRIs) or cognitive behavioral therapy 5

Potential Drug Interactions

• No significant drug interactions have been reported when NAC is used for skin picking
• NAC is also used as an antidote for acetaminophen poisoning 6, but this is a different indication requiring different dosing

While NAC shows promise for treating skin picking disorder, it should be considered as part of a comprehensive treatment approach that may include behavioral therapy and addressing underlying psychiatric comorbidities.