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Nursing Pharmacology Chapter 23: Ergot Alkaloids
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Chemistry and pharmacokinetics
Two Major Families:
Tetracyclic Ergoline Nucleus: Examples --
Lysergic acid diethylamide (LSD)
Ergonovine
Methysergide (Sansert)
6-methylergoline
Lysergic acid
Example peptide alkaloids:
Ergotamine
α-ergocryptine
Bromocriptine (Parlodel)
Ergot alkaloids are variably absorbed from the GI tract
Bromocriptine (Parlodel) is well absorbed from the GI tract
Metabolism:
These agents are extensively metabolized
Targets: several receptor types
Agonist effects
Partial agonist effects
Antagonist effects
Pre- and post-synaptic sites
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Ergot Alkaloids |
α-adrenergic receptor |
Dopamine receptor |
Serotonin receptor (5 HT2) |
Uterine smooth muscle stimulation |
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Bromocryptine |
- |
+++ |
- |
0 |
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Ergonovine |
++ |
- (Partial agonist) |
+++ |
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Ergotamine |
-- (Partial agonist) |
0 |
+ (Partial agonist) |
+++ |
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LSD |
0 |
+++ |
-- (++ in the CNS) |
+ |
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Methysergide |
+/0 |
+/0 |
--- (Partial agonist) |
+/0don't do anything |
Katzung, B. Histamine, Serotonin and the Ergot Alkaloids (The Ergot Alkaloids), in Basic and Clinical Pharmacology, (Katzung, B. G., Masters SB, Trevor AJ ed) Appleton-Lange, 12th edition, 2012, on-line edition
Burkhalter, A, Julius, D.J. and Katzung, B. Histamine, Serotonin and the Ergot Alkaloids (Section IV. Drugs with Important Actions on Smooth Muscle), in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 261-286.; New "Triptans" and Other Drugs for Migraine, The Medical Letter, Vol. 40 (Issue 1037); October 9, 1998
