What are the treatment options for headaches caused by neck stiffness, specifically the use of muscle relaxers like cyclobenzaprine (Flexeril) or metaxalone (Skelaxin)?

Muscle Relaxers for Headaches Due to Neck Stiffness

For headaches caused by neck stiffness, NSAIDs such as ibuprofen (400-600mg) or naproxen sodium (500-550mg) should be used as first-line treatment, rather than muscle relaxants like cyclobenzaprine or metaxalone. 1

Treatment Algorithm

First-Line Treatment

1. NSAIDs

   • Ibuprofen 400-600mg
   • Naproxen sodium 500-550mg
   • Diclofenac potassium

   These medications are recommended by the American College of Physicians as first-line treatments for headaches associated with muscle tension 1.

2. Combination analgesics containing caffeine

   • Aspirin + acetaminophen + caffeine combinations

   These are particularly effective for mild to moderate headaches with a muscular component 1.

Second-Line Treatment (if NSAIDs fail or are contraindicated)

1. Triptans

   • Sumatriptan 50mg orally (or 6mg subcutaneously for severe cases)
   • Rizatriptan 10mg orally

   Triptans are most effective when taken early in an attack while the headache is still mild 2.

Third-Line Treatment (if first and second-line treatments fail)

1. Muscle relaxants (with caution)
   • Cyclobenzaprine 5mg TID (preferable to 10mg due to fewer side effects) 3
   • Metaxalone 800mg TID

Evidence on Muscle Relaxants for Headaches

Cyclobenzaprine (Flexeril)

• Acts as a centrally acting 5-HT2 receptor antagonist and is structurally related to tricyclic antidepressants 2
• Can cause significant anticholinergic effects including hallucinations, confusion, drowsiness, constipation, urinary retention, and dry mouth 2
• Has shown efficacy for acute musculoskeletal pain with spasm, but evidence specifically for headaches is limited 4
• Lower doses (5mg TID) have been shown to be as effective as higher doses (10mg TID) with fewer sedative effects 3
• Combination therapy of cyclobenzaprine with NSAIDs has not shown superior efficacy compared to cyclobenzaprine alone 5

Metaxalone (Skelaxin)

• Centrally acting skeletal muscle relaxant with unclear mechanism of action 2
• Common side effects include drowsiness, dizziness, and irritability 2
• Contraindicated in patients with significant hepatic or renal dysfunction 2
• Limited evidence for efficacy in headache management specifically 4

Important Considerations and Precautions

When to Consider Muscle Relaxants

• Only after failure of first-line (NSAIDs) and second-line (triptans) treatments
• When muscle spasm is clearly identified as the primary cause of headache
• For short-term use only (typically 7-14 days)

Red Flags Requiring Further Evaluation

• Thunderclap headache
• Progressive headache
• Headache onset after age 50
• Neck stiffness with fever (possible meningitis)
• Headache associated with focal neurological symptoms
• Headache brought on by coughing, sneezing, or exercise 2

Contraindications for Muscle Relaxants

• Cyclobenzaprine:

  • Concomitant use with MAO inhibitors (risk of serotonin syndrome)
  • Cardiac arrhythmias, heart block, conduction disturbances
  • Hyperthyroidism
  • Acute recovery phase of myocardial infarction 6

• Metaxalone:

  • Significant hepatic or renal dysfunction
  • History of drug-induced hemolytic anemia 2

Medication Overuse Considerations

• Limit use of muscle relaxants to avoid medication overuse headache
• Cyclobenzaprine should not be used for more than 2-3 weeks without reassessment 6
• With long-term use, patients can experience withdrawal symptoms including malaise, nausea, and headache 2

Non-Pharmacological Approaches

• Regular aerobic exercise or strength training
• Maintaining regular sleep schedule
• Adequate hydration
• Identification and avoidance of triggers
• Relaxation techniques or mindfulness
• Physical therapy focused on neck muscles 1

Muscle relaxants should be used cautiously and only when other treatments have failed, as they have significant side effects and limited evidence specifically for headaches caused by neck stiffness. The most recent evidence supports using NSAIDs as first-line treatment for this condition.