Vinca alkaloid derivatives

Origin and chemical structure

The primary and practically sole representative of this pharmacological group in clinical practice is vinpocetine, also known by the trade name Cavinton.

Chemically, the drug is a semisynthetic derivative of the natural alkaloid vincamine. The initial raw materials used to obtain these compounds are medicinal plants with a narrow distribution range, specifically: lesser periwinkle (Vinca minor L.) and herbaceous periwinkle (Vinca erecta).

Molecular mechanism of action

The pharmacological effects of vinpocetine are based on several interrelated cellular processes:

• Myotropic antispasmodic effect: achieved due to the drug's ability to inhibit the enzyme phosphodiesterase.
• As a result of this enzymatic blockade, cyclic adenosine monophosphate (cAMP) accumulates within the smooth muscle cells of the vascular wall.
• The accumulation of cAMP leads to the relaxation of vascular smooth muscle and a subsequent decrease in vascular tone.

Effects on hemodynamics and rheology

Unlike many classical vasodilators, periwinkle alkaloid derivatives possess a unique vascular action profile:

1. Selectivity: the drug predominantly dilates cerebral blood vessels without exerting a pronounced effect on systemic circulation in other vascular beds.
2. Absence of the "steal" phenomenon: the medicinal product does not redirect blood to healthy tissues, but instead purposefully enhances blood supply specifically to ischemic areas suffering from oxygen deficiency.
3. Improvement of microcirculation: achieved by reducing blood viscosity, decreasing platelet aggregation tendency, and increasing erythrocyte deformability, allowing them to easily pass through the narrowest capillaries.

Metabolic effects and clinical application

The neuroprotective and metabolic action of vinpocetine is expressed in protecting nerve cells from oxygen deprivation. The drug helps neurons utilize oxygen more efficiently and enhances glucose uptake, shifting its oxidation to a more energy-efficient aerobic pathway.

Main indications for prescription:

• Chronic cerebrovascular insufficiency.
• Recovery period after a stroke.
• Various neuropsychiatric disorders associated with cerebrovascular pathology.
• Vascular ophthalmological diseases of the eye.
• Hearing loss of toxic or vascular origin in otorhinolaryngology.

Route of administration and side effects

The drug is taken orally in long-term courses, and when emergency care is required, intravenous drip administration is used.

• Potential side effects:
• General reactions: moderate decrease in blood pressure, nausea, dizziness.
• Risks with rapid intravenous administration: occurrence of tachycardia, extrasystole, or slowed intraventricular conduction.

Class and exam questions

What else to study on this topic

• Chemical relationship of vinpocetine with the natural alkaloid vincamine
• Biochemical mechanisms of aerobic glucose oxidation in neurons under the action of neuroprotectants
• Effect of erythrocyte deformability on the microcirculatory bed
• Pharmacokinetics and features of long-term oral administration of vinpocetine
• Comparison of cardiovascular risks with slow and rapid intravenous administration

Other topics in the section "Drugs used for cerebral circulatory disorders"

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