Symptoms of monoamine oxidase inhibitor (MAOI) overdose  can be similar to the medication’s side effects, but are usually more severe. They may start slowly over a period of 24 to 48 hours and can persist for two weeks. In some cases, they may progress to patient coma and – at least in the case of the MAOI tranylcypromine – death. Patients exhibiting any of these symptoms should contact their physician immediately:

• Agitation
  
• Flushing
  
• Tachycardia (rapid heart rate)
  
• Hypotension (low blood pressure) or hypertension (high blood pressure)
  
• Palpitations
  
• Increased motor activity
  
• Twitching
  
• Increased deep tendon reflexes
  
• Seizures
  
• Hyperpyrexia (abnormally high fever)
  
• Cardiorespiratory arrest