What medications are risky to use in patients with Henoch-Schönlein Purpura (HSP)?

Medications to Avoid in Henoch-Schönlein Purpura (HSP)

NSAIDs should be avoided in patients with HSP due to the high risk of exacerbating gastrointestinal bleeding and worsening renal function in a disease already characterized by these complications. 1

High-Risk Medications

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs)

• Avoid NSAIDs entirely in HSP patients, particularly those with gastrointestinal involvement (present in 63-82% of cases) or renal involvement (present in 40-57% of cases) 1, 2, 3
• NSAIDs are contraindicated in patients with GFR < 30 ml/min/1.73 m² and prolonged therapy is not recommended when GFR < 60 ml/min/1.73 m², which is relevant given HSP's propensity for renal involvement 1
• NSAIDs should not be used in patients taking RAAS blocking agents (ACE inhibitors or ARBs), which may be prescribed for HSP nephritis management 1
• The risk of gastrointestinal bleeding is particularly concerning as 33% of HSP patients already experience GI bleeding as part of their disease manifestation 3

Nephrotoxic Agents

• Aminoglycosides require dose reduction and careful monitoring when GFR < 60 ml/min/1.73 m², with mandatory serum level monitoring (trough and peak) and avoidance of concomitant ototoxic agents like furosemide 1
• Amphotericin should be avoided unless no alternative exists when GFR < 60 ml/min/1.73 m² 1
• Methotrexate requires dose reduction when GFR < 60 ml/min/1.73 m² and should be avoided if possible when GFR < 15 ml/min/1.73 m² 1

Anticoagulants (Use with Extreme Caution)

• Low-molecular-weight heparins require dose reduction by 50% when GFR < 30 ml/min/1.73 m², with consideration for switching to conventional heparin or monitoring plasma anti-factor Xa in high bleeding risk patients 1
• Warfarin carries increased bleeding risk when GFR < 30 ml/min/1.73 m², requiring lower doses and close monitoring 1
• Given that HSP already causes vasculitis with bleeding manifestations (purpura in 100% of patients, GI bleeding in 33%), anticoagulation must be approached with exceptional caution 2, 3

Medications Requiring Dose Adjustment in HSP with Renal Involvement

Antimicrobials

• Penicillin: Risk of crystalluria and neurotoxicity with benzylpenicillin when GFR < 15 ml/min/1.73 m² (maximum 6 g/day) 1
• Macrolides: Reduce dose by 50% when GFR < 30 ml/min/1.73 m² 1
• Fluoroquinolones: Reduce dose by 50% when GFR < 15 ml/min/1.73 m² 1
• Tetracyclines: Reduce dose when GFR < 45 ml/min/1.73 m² as they can exacerbate uremia 1

Antihypertensives (If Renal Involvement Present)

• RAAS antagonists (ACE inhibitors, ARBs) should be started at lower doses when GFR < 45 ml/min/1.73 m², with GFR and potassium assessment within 1 week of starting or dose escalation 1
• Temporarily suspend RAAS antagonists during intercurrent illness, planned IV radiocontrast administration, or bowel preparation prior to colonoscopy 1
• Beta-blockers: Reduce dose by 50% when GFR < 30 ml/min/1.73 m² 1

Critical Clinical Context

Renal Function Monitoring is Essential

• 40-57% of HSP patients develop nephritis, making renal function assessment mandatory before prescribing any medication 2, 3, 4
• Older children and adolescents (>7 years) have significantly higher rates of renal involvement (57.1%) compared to younger children 4
• Follow-up should include regular urine testing for proteinuria and hematuria and blood pressure measurement for at least 6 months 5

Gastrointestinal Considerations

• 63-82% of HSP patients have abdominal pain, and 33% experience GI bleeding 2, 3
• Any medication that increases GI bleeding risk (NSAIDs, anticoagulants) or requires intact GI absorption should be carefully reconsidered 2, 3

Safe Analgesic Alternative

• Acetaminophen (paracetamol) is the preferred analgesic for pain management in HSP patients, as it does not carry the same GI and renal risks as NSAIDs 6