Migraine medications Flashcards
What is the role of serotonin in migraine symptomatology ?
The level of 5HT is increased during aura leading to vasoconstriction and decreases during migraine attack triggering vasodilation. The serotonin mediated change in vessel caliber activates pain receptors leading to headache.
What is the cause of photosensitivity, phonosensitivity, and smell sensitivity in migraine ?
It is due to the cortical spreading depression caused by the aural phase hike in 5HT.
What are the two types of therapeutic approach to migraine ?
- Acute symptomatic Tx
- Prophylactic Tx.
What are the drugs of choice for mild to moderate migraine attacks ?
NSAIDS, and opioid agonist Butorphanol.
What are the drugs for acute severe migraine attacks ?
The 5HT agonists such as Triptans and Ergot alkaloids as they mimic serotonin to cause vasoconstriction.
What is the indication for prescribing Triptans ?
Patients with mild symptoms who do not respond to analgesics or when symptoms are moderate to severe.
What are the most commonly ued triptans ?
Sumatriptan, Zolmitriptan, Naratriptan and Rizatriptan.
What is the parenteral form of triptan available for the Tx of migraine with severe symptoms ?
Subcutaneous or nasal sumatriptan.
What is the MOA of triptans ?
They bind to 5HT- 1B and 1D receptors and prevent vasoactive peptide release leading to the inhibition of trigeminal pain receptor activation and induces vasoconstriction.
What are the side effects of Triptans ?
- Parasthesia and dizziness.
- High BP and coronary vasospasm.
What is the contraindication for triptans ?
CV diseases due to the risk of angina and MI.
What is the risk of co-administering triptans with other serotonin receptor agonists ?
Serotonin syndrome
What is the clinical presentation of serotonin syndrome ?
Cognitive: Headache, Hallucinations and coma.
Somatic : tremor and hyperreflexia
autonomic: tachicardia, nausea, diarrhoea, shivering and sweating.
What are the common ergot alkaloids used in migraine patients who do not respond to triptans ?
Ergotamine ( sublingual ) and dihydroergotamine (IM or IN).
why does ergotamines cause emesis ?
They are non-specific 5HT receptor agonists. Therefore they can bind to the 5HT 3 receptors at the area postrema leading to nausea and vomiting.
What is the contraindication for ergotamines ?
CVD and HTN, Liver disease
Why is ergotamine contraindicated in pregnant woman ?
It can cause Premature labor, foetal distress and miscarriage due to its oxytocin like effect on the uterine myomterium.
What is ergotism ?
It is an ergot overdose condition which manifests as spasms, seizures, gangraine in hands and feet, GI and psych symptoms.
What is the management of Ergotism ?
Anticoagulants, vasodilators, and low molecular weight dextran.
What are the beta blocker used as firstline prophylaxis for chronic migraine ?
Propranolol, Nandolol, Temolol, and metoprolol
What is the calcium channel blockers used as prophylaxis for the Tx of chronic migraine ?
Verapamil
What is the most common TCA used as prophylaxis for the Tx of chronic migraine ?
Amytriptyline.
What is the anti- seizure medication used as prophylaxis for the Tx of chronic migraine ?
Topiramate.
What is the last line prophylaxis for Migraine ?
Onabotulinum toxin A or Botox injection as they block nociceptive neurotransmiter release in trigeminal neurones.
What are the Anti- CGRP antibodies used as prophylaxis for chronic migraine ?
Erenumab, Fermanezumab, and Galcanezumab. All are administered subcut. These are monoclonal antibodies that block CGRP or its receptors.
What is the action of CGRP ?
These are peptide neurotransmitters involved in augmenting sensory trigeminal transmission which is a key pathological mechanism in migraine headache.
What is the advantage of Anti-CGRP monoclonal antibodies ?
They have less side effects and no drug to drug interactions.
