Clozapine Monitoring and Management

Monitoring Requirements

1. Blood (Neutropenia/Agranulocytosis)

   • FBC Frequency:

     • Weekly for first 18 weeks → Fortnightly from weeks 18–52 → Monthly after 1 year if stable

   • Action:

     • Cease if neutrophils <1.5 × 10⁹/L; consult psychiatrist

     • Monitor closely if neutrophils 1.5–2.0 × 10⁹/L

2. Cardiovascular

   • Troponin/CRP: Weekly for first 4 weeks to detect myocarditis

   • Echocardiogram: Baseline, then annually (risk of cardiomyopathy)

   • ECG: Every 6–12 months or more often during initiation

3. Metabolic Monitoring

   • Weight, BMI, waist circumference: At every GP visit

   • Lipids and glucose: Every 6 months

4. Other

   • Clozapine Levels: Every 6 months or if smoking cessation, drug changes, or clinical concerns (e.g. seizures)

   • Constipation: Screen each visit (life-threatening risk if severe)

Adverse Effects

1. Constipation

   • Prevent aggressively with stool softeners/laxatives (e.g. docusate + senna)

2. Seizures

   • Risk increases if clozapine levels exceed 600 µg/L

   • Treat with sodium valproate (under specialist guidance)

3. Hypersalivation

   • Manage with non-pharmacological measures or sublingual atropine drops

Myocarditis and Cardiomyopathy

• Myocarditis

  • Onset typically in the first 4 weeks

  • Signs include tachycardia, fever, chest pain

  • Monitoring involves troponin, CRP, ECG

• Cardiomyopathy

  • Median onset around 9 months

  • Symptomatic presentations require same-day cardiology review (ECG/echo)

Clozapine Poisoning

• Key Investigations

  • ECG for QT prolongation or arrhythmias

  • FBC for neutrophil/granulocyte counts

  • Bladder ultrasound to check for urinary retention

• Management

  • Supportive care: Airway protection, IV fluids for hypotension

  • Seizures: IV benzodiazepines

  • Activated charcoal if within 2 hours and patient cooperative (or via NG tube if intubated)

• Discharge Advice

  • Monitor for sedation/cognitive impairment for 3 days post-discharge

  • Avoid driving or operating heavy machinery

Notes

• If therapy is interrupted for >48 hours, re-titrate the dose to avoid severe hypotension or seizures.