Medication Overuse Headache

1. Definition (ICHD-3 )

Medication Overuse Headache (MOH) is a secondary headache disorder defined as:

• Headache occurring on ≥15 days/month
• In a patient with a pre-existing primary headache disorder
• Due to regular overuse of acute/symptomatic headache medication for >3 months

Typical question:

A patient with migraine takes sumatriptan daily and develops daily headache → diagnosis?

👉 Answer: Medication overuse headache

2. Diagnostic Criteria (ICHD-3)

A. Headache Criteria

• ≥15 days/month

B. Drug Overuse Thresholds 

3. Common Causative Drugs

High-risk 

• Triptans
• Ergot derivatives
• Opioids
• Combination analgesics (especially caffeine-containing)

Moderate risk

• NSAIDs

Lower risk

• Paracetamol (but still causative if frequent)

4. Pathophysiology 

A. Central Sensitization

• Chronic exposure → ↓ pain threshold
• Increased excitability of trigeminovascular system

B. Neurotransmitter Changes

• ↓ serotonin (5-HT)
• ↑ CGRP activity
• Dopaminergic dysregulation

C. Functional Brain Changes

• Altered activity in:
• Periaqueductal gray
• Hypothalamus
• Orbitofrontal cortex

D. Dependence-like Mechanism

• Especially with:
• Opioids
• Caffeine-containing drugs

5. Epidemiology

• Prevalence: ~1–2% general population
• More common in:
• Females (3:1)
• Patients with:
• Migraine (most common underlying disorder)
• Tension-type headache

6. Risk Factors

• High baseline headache frequency
• Psychiatric comorbidity:
• Depression
• Anxiety
• Sleep disorders
• High caffeine intake
• Poor access to preventive therapy

7. Clinical Features 

Typical Pattern

• Daily or near-daily headache
• Often:
• Diffuse
• Dull/pressure-like

Key Clues 

• Headache worsens on waking
• Temporary relief after medication → recurrence
• Escalating medication use

Associated Features

• Nausea
• Irritability
• Poor concentration

8. Types of MOH (Based on Drug)

9. Diagnosis

Clinical Diagnosis (No test confirms MOH)

Important Steps:

1. Detailed drug history
2. Headache diary
3. Exclude secondary causes

Red Flags (NOT MOH → investigate)

• Sudden onset (thunderclap)
• Focal deficits
• Fever, cancer, immunosuppression

10. Management ( NICE, EFNS, AHS)

• NICE:
• Advise abrupt withdrawal + education
• European Federation of Neurological Societies:
• Early preventive therapy improves outcomes
• American Headache Society:
• Emphasizes CGRP pathway and behavioral therapy

STEP 1: Patient Education (MOST IMPORTANT)

• Explain:
• Cause = medication overuse
• Withdrawal is necessary
• Improves compliance and outcomes

STEP 2: Withdrawal of Offending Drug

A. Abrupt Withdrawal (Preferred)

• For:
• Triptans
• NSAIDs
• Paracetamol

B. Gradual Withdrawal

• For:
• Opioids
• Benzodiazepines

Withdrawal Symptoms 

• Worsening headache (2–10 days)
• Nausea/vomiting
• Sleep disturbance
• Anxiety

STEP 3: Bridge (Transitional) Therapy

Used during withdrawal phase:

• NSAIDs (if not causative)
• Antiemetics:
• Metoclopramide
• Steroids (controversial, sometimes used)

STEP 4: Preventive Therapy (START EARLY)

Migraine prevention options:

• Beta-blockers (propranolol)
• Topiramate
• Amitriptyline
• CGRP monoclonal antibodies (advanced)

STEP 5: Non-Pharmacological

• Cognitive behavioral therapy
• Sleep hygiene
• Stress management

11. Prognosis

• 50–70% improve after withdrawal
• Relapse rate:
• ~30–40% within 1 year

Poor Prognostic Factors

• Opioid overuse
• Psychiatric illness
• Poor adherence

12. Complications

• Chronic migraine transformation
• Drug dependence
• Reduced quality of life

13. Important Differentials 

• Chronic migraine
• Chronic tension-type headache
• New daily persistent headache

👉 Key difference: MOH improves after drug withdrawal