ERGOT ALKALOIDS

Question 1

Ergot Alkaloids are usually produced by the fungus?

Answer 1

Claviceps purpurea - may infect grasses and grains.

Question 2

What are the major actions of ergot alkaloids?

Answer 2

• Act as partial agonists at alpha adrenoceptors and 5HT receptors.
• Act as potent agonists at dopamine receptors.

Question 3

Outline the 3 major subgroups of ergot alkaloids based on their primary effects.

Answer 3

• Vessels e.g Ergotamine - causes prolonged vasoconstriction .
• Uterus e.g Ergonovine - causes powerful uterine contractions.
• Brain
  – Lysergic acid Diethylamide causes prominent hallucinations .
  – Pergolide & bromocriptine inhibit prolactin release ( potent dopamine agonists).

Question 4

Outline the major clinical applications of Ergot Alkaloids.

Answer 4

• Used in treatment of migraines.
• Management of post Partum Haemorrhage.
• Treatment of hyperprolactinaemia & Parkinsonism.

Question 5

List down the major Ergot Alkaloids commonly used in treatment of migraines.

Answer 5

• Ergotamine
• Methysergide
• Dihydroxyergonovine
• Ergonovine
• Triptan derivatives

Question 6

Which ergot alkaloids are used in management of postpartum hemorrhage?

Answer 6

• Ergonovine
• Ergotamine
  – must not be given before placental delivery because they cause powerful and prolonged uterine contractions that may result in abortion.

Question 7

Describe the features of ergot Alkaloid toxicity.

Answer 7

• Prolonged use of Ergotamine & Ergonovine can result in prolonged vasoconstriction, resulting in ischemia & gangrene which may necessitate amputation .
• Hyperplasia of connective tissue which may result in hydronephrosis ( retroperitoneal) and cardiac valvular & conduction abnormalities ( subendocardial).
• Nausea , vomiting, diarrhea.
• Marked contractions which may result in abortion.
• Hallucinations resembling psychosis with chronic use of LSD.

Question 8

What is the most effective antidote used to reverse ergot Alkaloid toxicity?

Answer 8

• Nitroprusside
• Nitroglycerin

Question 9

The maximum dose of Ergotamine per week in treatment of migraines is ?

Answer 9

10 mg

Question 10

Which drug causes vasoconstriction despite being an alpha - adrenergic blocker?

Answer 10

Ergotamine

Question 11

How does dihydro-ergotamine different from Ergotamine?

Answer 11

It is a more potent alpha adrenergic blocker and a less potent vasoconstrictor.

Question 12

Ergotamine relieves migraines by?

Answer 12

Constricting cranial vessels and reducing perivascular neurogenic inflammation.

Question 13

Most useful ergot derivatives used in treatment of hyperprolactinaemia?

Answer 13

• Bromocriptine
• Pergolide
• Cabergoline

Question 14

Speed of absorption & peak blood levels of Ergotamine after oral administration can be improved by?

Answer 14

Intake of caffeine alongside the drug .
– 100mg of caffeine for each 1mg of Ergotamine.

Question 15

The drug of choice for controlling postpartum hemorrhage is?

Answer 15

Methyl - ergometrine

Question 16

Major difference between the Amine Alkaloids & Peptide Alkaloids?

Answer 16

• Amine alkaloids are derived from ammonia, while peptide alkaloids are derived from amino acids.
  *Amine Alkaloids have higher bioavailability due to better solubility, absorption, and stability while Peptide Alkaloids have Lower bioavailability because of enzymatic degradation, larger size, and poor membrane permeability.