Migrane for 5 marks refer kdt
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I now have comprehensive content. Let me compile the complete 5-mark answer based on KDT-style pharmacology (Katzung is the "K" in KDT - Katzung, Davis, Trevor).
Migraine - Pharmacological Treatment (5 Marks)
(KDT = Katzung, Davis & Trevor - Basic & Clinical Pharmacology)
Pathophysiology (Brief)
Migraine is a neurovascular disorder. In classic migraine (with aura), a spreading cortical depression causes hypoperfusion starting posteriorly and spreading forward. In both types, the headache phase involves extracranial and intracranial arterial vasodilation, releasing neuroactive peptides - substance P, neurokinin A, and calcitonin gene-related peptide (CGRP) - from trigeminal nerve endings, triggering pain.
- Classic migraine: preceded by aura (visual scotomas, hemianopsia, paresthesias, speech abnormalities) followed by severe throbbing unilateral headache for hours to 1-2 days
- Common migraine: same headache but no aura
- Chronic migraine: daily or near-daily headache, treated prophylactically
Treatment
A. Acute (Abortive) Treatment
1. Triptans (5-HT1B/1D Receptor Agonists) - FIRST LINE
Drugs: Sumatriptan, almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, zolmitriptan
Mechanism: Selective agonists at 5-HT1B/1D receptors on meningeal/cerebral vessels and trigeminal nerve endings:
- Cause vasoconstriction of dilated vessels
- Inhibit release of vasodilating proinflammatory neuropeptides (CGRP, substance P) from trigeminal nerve endings
Pharmacokinetics:
- Sumatriptan: SC (onset 20 min), intranasal, or oral (onset 1-2 hr); t½ = 2 hr
- Frovatriptan: longest acting, t½ > 24 hr
- Headache recurs within 24-48 hr; a second dose is usually effective
Efficacy: Abort or markedly reduce migraine in ~70% of patients
Adverse effects: Chest/neck/jaw pressure and pain, dizziness, malaise, elevated BP, cardiac events
Contraindication: Coronary artery disease (vasoconstrictive effect); cardiac evaluation required if CAD risk factors present
2. Ergot Alkaloids
Drugs: Ergotamine, Dihydroergotamine (DHE)
Mechanism: Non-selective serotonin receptor agonists; also activate 5-HT1B/1D receptors - cause vasoconstriction of cranial vessels; also inhibit trigeminal peptide release
- Ergotamine: oral or rectal (often combined with caffeine to enhance absorption)
- DHE: parenteral (SC, IM, IV) or nasal spray
Adverse effects: Nausea, vomiting (major), peripheral vasoconstriction, ergotism with overuse
Contraindications: Cardiovascular disease, pregnancy, hypertension
3. CGRP Receptor Antagonists (Gepants) - Newer
Drugs: Ubrogepant, Rimegepant (oral), Atogepant
Mechanism: Block CGRP receptor, preventing vasodilation and neurogenic inflammation triggered by CGRP release
Advantage: No vasoconstrictive effect - safe in patients with CAD or triptan contraindications
4. Ditans (5-HT1F Agonists)
Drug: Lasmiditan (50-200 mg)
Mechanism: Selective 5-HT1F agonist - inhibits trigeminal pain signaling WITHOUT vasoconstriction
Advantage: No cardiovascular risk
5. Nonspecific / Adjuncts
- NSAIDs (aspirin, ibuprofen, naproxen): useful for mild-moderate attacks
- Antiemetics (prochlorperazine, metoclopramide IV/IM): control nausea/vomiting; metoclopramide also has direct antimigraine effect
- Opioids: rarely, for refractory cases only
B. Prophylactic (Preventive) Treatment
Indicated when: Attacks occur ≥2 times/month OR headaches are severe/complicated by neurologic signs
| Drug Class | Drugs | Notes |
|---|---|---|
| β-Blockers (first choice) | Propranolol, metoprolol | Most evidence; reduce frequency |
| Antiepileptics | Valproate, topiramate | Also effective |
| Tricyclic antidepressants | Amitriptyline | Especially if comorbid depression |
| Calcium channel blockers | Verapamil | Alternative |
| Anti-CGRP monoclonal antibodies | Erenumab, fremanezumab, galcanezumab | Newest; given monthly SC; for chronic/refractory migraine |
Mechanism of prophylaxis: β-blockers and antiepileptics suppress excessive trigeminal firing; CGRP mAbs block CGRP-mediated neurogenic vasodilation chronically
Summary Table
| Category | Drug | Mechanism |
|---|---|---|
| Abortive - 1st line | Triptans (sumatriptan) | 5-HT1B/1D agonist → vasoconstriction + ↓CGRP/SP release |
| Abortive | Ergotamine, DHE | Non-selective 5-HT agonist → vasoconstriction |
| Abortive - newer | Ubrogepant, rimegepant | CGRP receptor antagonist |
| Abortive - newer | Lasmiditan | 5-HT1F agonist (no vasoconstrictiion) |
| Symptomatic | NSAIDs, antiemetics | Anti-inflammatory, antiemetic |
| Prophylaxis | Propranolol | β-blocker |
| Prophylaxis | Valproate, topiramate | Antiepileptic |
| Prophylaxis - new | Erenumab | Anti-CGRP mAb |
Sources: Katzung's Basic & Clinical Pharmacology 16th Ed.; Lippincott Illustrated Reviews: Pharmacology
Witg classification
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I have all the content needed. Here is the complete Classification of Drugs used in Migraine as per KDT (Katzung):
Classification of Drugs Used in Migraine
(As per KDT - Katzung's Basic & Clinical Pharmacology)
I. ABORTIVE (Acute) Drugs
(Used to terminate an ongoing attack)
A. Migraine-Specific Drugs
1. 5-HT1B/1D Receptor Agonists - Triptans (First Line)
- Sumatriptan (prototype)
- Almotriptan
- Eletriptan
- Frovatriptan (longest acting, t½ >24 hr)
- Naratriptan
- Rizatriptan
- Zolmitriptan
2. Ergot Alkaloids
- Ergotamine tartrate (oral/rectal; often + caffeine)
- Dihydroergotamine - DHE (parenteral/nasal)
3. 5-HT1F Receptor Agonists (Ditans) (Newer)
- Lasmiditan (no vasoconstriction - safe in CAD)
4. CGRP Receptor Antagonists - Gepants (Newer)
- Ubrogepant (oral)
- Rimegepant (oral) (safe when triptans are contraindicated)
B. Nonspecific (Symptomatic) Drugs
5. NSAIDs / Analgesics
- Aspirin
- Ibuprofen
- Naproxen
- Paracetamol (mild attacks)
6. Antiemetics (also have direct antimigraine effect)
- Metoclopramide (IV/IM - first choice)
- Prochlorperazine
- Domperidone
7. Opioids (rarely, refractory cases only)
- Codeine, tramadol
II. PROPHYLACTIC (Preventive) Drugs
(Given daily to reduce attack frequency/severity)
Indication: ≥2 attacks/month OR severe/complicated attacks
| Class | Drugs | Line |
|---|---|---|
| β-Blockers | Propranolol, metoprolol, atenolol | 1st line |
| Antiepileptics | Valproic acid, topiramate | 1st line |
| Tricyclic antidepressants | Amitriptyline | 1st line |
| Ca²⁺ channel blockers | Verapamil, flunarizine | 2nd line |
| SSRIs/SNRIs | Venlafaxine | 2nd line |
| Anti-CGRP mAbs | Erenumab, fremanezumab, galcanezumab, eptinezumab | 2nd line (cost) |
| Botulinum toxin | OnabotulinumtoxinA | Chronic migraine |
Quick Memory Aid
Abortive: TENT-OG
T - Triptans (5-HT1B/1D)
E - Ergots
N - NSAIDs
T - (di)Tans / Lasmiditan (5-HT1F)
O - Oral gepants (CGRP antagonists)
G - Gut drugs (antiemetics)
Prophylactic: β-ACVB
β - Beta blockers (propranolol)
A - Antiepileptics (valproate, topiramate)
C - Ca channel blockers (verapamil)
V - Venlafaxine / TCAs (amitriptyline)
B - Biologics (anti-CGRP mAbs)
Source: Katzung's Basic & Clinical Pharmacology, 16th Ed. (KDT), Chapter 16
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