Chemical structure and pharmacokinetics
The sole main representative of the group under consideration is nicergoline. Structurally, the substance is a synthetic derivative of ergot alkaloids. A feature of its molecular structure is an attached brominated nicotinic acid residue.
The drug can be administered via various routes depending on the clinical situation:
- Enterally (oral administration).
- Parenterally (including intravenous administration).
Mechanism of pharmacological action
The pharmacological response of the body to drug administration is due to a combined mechanism, which includes two essential components:
- Alpha-adrenoblocking effect — consists in the targeted blockade of vasoconstrictor adrenoceptors.
- Direct myotropic effect — provides direct relaxation of the vascular wall smooth muscle (spasmolytic effect).
Pharmacodynamic effects and hemodynamics
Due to the combination of receptor and myotropic properties, the drug has a pronounced effect on the vascular system. The main vascular targets are cerebral arterioles and peripheral vessels.
The systemic hemodynamic response manifests as follows:
- Dilatation of cerebral arterioles.
- Dilatation of the peripheral vascular bed.
- Overall improvement of hemodynamics and blood supply in various vascular beds: cerebral, pulmonary, renal, and in the extremities.
Oral administration of the drug in therapeutic doses does not affect blood pressure. However, intravenous administration carries a risk of developing a hypotensive effect (decrease in BP).
Indications and adverse reactions
The presence of vasodilating properties determines the main clinical indications for prescribing the medicinal product:
- Cerebral circulation disorders developing against the background of atherosclerosis or thromboembolism.
- Peripheral circulation disorders.
During pharmacotherapy, adverse effects may develop:
- Vestibular disorders in the form of dizziness.
- Allergic and skin manifestations (pruritus).
- Gastrointestinal disorders (dyspepsia).
Briefly: answers to topical questions
What other drugs belong to the ergot alkaloid derivatives group, besides nicergoline?
The group of ergot alkaloid derivatives includes various drugs used as vascular agents, medications affecting myometrial tone, and dopamine receptor agonists:
- Ergometrine (ergometrinum) is an ergot alkaloid that increases myometrial tone.
- Ergotamine (ergotaminum) is an ergot alkaloid.
- Bromocriptine (bromocriptinum) is an ergot alkaloid derivative and a dopamine receptor agonist.
- Pergolide (pergolidum) is an ergot alkaloid derivative and a dopamine receptor agonist.
- Lisuride (lisuridum) is an ergot alkaloid.
With what receptor types, besides alpha-adrenoceptors, do ergot alkaloid derivatives interact?
Ergot alkaloid derivatives interact with dopamine receptors in addition to alpha-adrenoceptors. Specifically, drugs in this group such as bromocriptine and pergolide are direct dopamine receptor agonists, showing the highest activity at $D_2$-type receptors.
Nicergoline = bromine + nicotinic acid: blocks alpha-receptors, relaxes vascular smooth muscle, treats the brain and extremities, but drops blood pressure when given IV.
Class and exam questions
Which main representative belongs to ergot alkaloid derivatives in this topic?
The main representative is nicergoline (known under the trade name Sermion).
What are the features of the chemical structure of nicergoline?
It is a synthetic ergot alkaloid derivative that contains a brominated nicotinic acid residue.
Does the drug alter blood pressure when taken orally?
When administered orally in therapeutic doses, the drug does not affect blood pressure, whereas intravenous administration can cause a hypotensive effect.
What else to study on this topic
- Features of the alpha-adrenoceptor blocking activity of ergot derivatives
- Comparison of the pharmacodynamics of myotropic antispasmodics and vasodilators
- Pathogenesis of cerebrovascular disorders in atherosclerosis and thromboembolism
- Differentiated approach to enteral and parenteral administration of vasoactive agents
- Pharmacological correction of peripheral circulation disorders
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