Medication overuse headache

Epidemiology & Risk Factors

• Underlying primary headache disorder (Migraine > Tension-Type Headache [TTH]).
• Regular abortive med overuse for $\ge 3\text{ months}$:
  • $\ge 10\text{ days/month}$: Triptans, opioids, ergotamines, butalbital.
  • $\ge 15\text{ days/month}$: NSAIDs, Acetaminophen (APAP), Aspirin.
• The pathophysiologic mechanism is likely due to an interplay between genetic predisposition and central pain sensitization with alteration of neuronal excitability.

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Clinical Features

• Chronic headache $\ge 15\text{ days/month}$, characteristically present upon awakening. c
  • Because analgesics wear off during the night while patients are sleeping
• Rebound cycle: Transient relief post-dose $\to$ headache recurs as drug clears.
• Normal physical and neurologic examination.

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Diagnosis

• Clinical: Pre-existing HA + headache $\ge 15\text{ d/mo}$ + abortive overuse $>3\text{ mo}$.
• Initial Step: Detailed medication reconciliation and headache diary.
• Neuroimaging (Brain MRI/CT): Indicated only if red flags are present (SNOOP criteria: focal deficits, papilledema, onset $\ge 50\text{ yo}$, sudden thunderclap onset).

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Differential Diagnostics

• Chronic Migraine: Diff by $\ge 15\text{ d/mo}$ with migrainous features in the absence of abortive medication overuse.
• Idiopathic Intracranial Hypertension (IIH): Diff by obese young female, papilledema, pulsatile tinnitus, and LP opening pressure $>250{\text{ mm H}}_2\text{O}$.
• Giant Cell Arteritis (GCA): Diff by age $\ge 50$, jaw claudication, scalp tenderness, and $\uparrow$ ESR/CRP.

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Management

• First-line (Definitive):
  1. Discontinue offending drug: Abrupt stop for NSAIDs/triptans; slow taper for opioids/butalbital (prevents withdrawal/seizures). c
  2. Patient education: HA will worsen for 2–10 days before improving over 2–12 weeks.
• Bridge Therapy (Short-term, $<2\text{ weeks}$):
  • Prednisone taper or antiemetics (e.g., Metoclopramide) to mitigate rebound symptoms.
• Preventive Therapy (Initiate immediately at withdrawal):
  • Topiramate, TCAs (Amitriptyline), or Beta-blockers (Propranolol).
• Refractory: Inpatient medically-supervised detoxification.

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Complications

• Refractory chronic daily headache.
• Drug-specific organ toxicity: NSAIDs $\to$ PUD/CKD; APAP $\to$ hepatotoxicity; Barbiturates $\to$ withdrawal seizures.