What is the mechanism of action of a medication?

From the Guidelines

The mechanism of action of a medication is the specific biochemical process by which a drug produces its therapeutic effect, and understanding this is crucial for predicting its effects, potential side effects, and appropriate clinical applications. The mechanism of action of a medication refers to the specific biochemical process through which a drug interacts with cellular targets such as receptors, enzymes, ion channels, or other molecular structures to alter physiological functions. For instance, bile acid sequestrants, such as colesevelam, work by binding bile acids in the intestine, impeding their reabsorption, and ultimately increasing the clearance of LDL particles from the blood, resulting in decreased serum LDL-C levels 1.

• Key aspects of a medication's mechanism of action include:
  • The specific biochemical process involved
  • The interaction with cellular targets
  • The alteration of physiological functions
  • The resulting therapeutic effect
• Examples of medications and their mechanisms of action include:
  • Bile acid sequestrants, such as colesevelam, which bind bile acids in the intestine and increase the clearance of LDL particles from the blood 1
  • HMG-CoA reductase inhibitors, such as atorvastatin, which inhibit cholesterol synthesis in hepatic cells and decrease the cholesterol pool, resulting in the upregulation of LDL receptors 1
  • Cholesterol absorption inhibitors, such as ezetimibe, which inhibit the intestinal absorption of cholesterol and plant sterols, decreasing the hepatic cholesterol pool and upregulating LDL receptors 1

The most recent and highest quality study, published in 2022, provides updated information on the mechanism of action of various medications, including inclisiran and bile acid sequestrants. This study highlights the importance of understanding the mechanism of action of medications in order to predict their effects, potential side effects, and appropriate clinical applications 1.

• The study provides information on the mechanism of action of inclisiran, which is a new medication for the treatment of hyperlipidemia
• The study also provides updated information on the mechanism of action of bile acid sequestrants, including colesevelam, and their use in the treatment of hyperlipidemia 1
• The study emphasizes the importance of considering the mechanism of action of medications when selecting treatment options for patients with hyperlipidemia.

From the FDA Drug Label

Metoprolol is a beta 1-selective (cardioselective) adrenergic receptor blocker. The mechanism of the antihypertensive effects of beta-blocking agents has not been fully elucidated However, several possible mechanisms have been proposed: (1) competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic neuron sites, leading to decreased cardiac output; (2) a central effect leading to reduced sympathetic outflow to the periphery; and (3) suppression of renin activity By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction and in blood pressure, metoprolol reduces the oxygen requirements of the heart at any given level of effort, thus making it useful in the long-term management of angina pectoris

The mechanism of action of the medication, specifically beta-blockers (PO), is through beta 1-selective adrenergic receptor blockade. This leads to several effects, including:

• Competitive antagonism of catecholamines at peripheral adrenergic neuron sites
• Central effect leading to reduced sympathetic outflow to the periphery
• Suppression of renin activity
• Reduction of oxygen requirements of the heart by blocking catecholamine-induced increases in heart rate and blood pressure 2

From the Research

Mechanism of Action of Medication

The mechanism of action of a medication refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect.

• Pharmacokinetic Interactions: These occur when one drug affects the absorption, distribution, metabolism, or excretion of another drug 3, 4, 5. For example, interactions with cytochrome P450 enzymes can alter drug metabolism, while interactions with P-glycoproteins can affect drug absorption.
• Pharmacodynamic Interactions: These occur when two or more drugs act on the same receptor site to produce additive or superadditive effects (synergism) or diminish the effect of another drug (antagonism) 3, 4, 5.
• Biochemical Mechanism of Action: Drugs can be classified into different classes based on their biochemical mechanism of action, such as signal-transduction systems, components of plasmatic membranes, intracellularly, gene therapy, extracellularly, or invasive agents 6.
• Drug Class Effects: The concept of drug class effect is based on similar chemical structure, mechanism of action, or pharmacological effects 7. This concept is important in clinical practice, as it allows for the selection of specific drugs within a class based on their efficacy and safety profiles.

Types of Mechanisms

There are various types of mechanisms through which medications interact, including:

• Signal-Transduction Systems: Drugs can interact with signal-transduction systems, such as G-protein coupled receptors or enzyme-linked receptors 6.
• Plasmatic Membranes: Drugs can interact with components of plasmatic membranes, such as ion channels or transporters 6.
• Intracellularly: Drugs can interact with intracellular targets, such as enzymes or receptors 6.
• Gene Therapy: Drugs can interact with genetic material, such as DNA or RNA 6.
• Extracellularly: Drugs can interact with extracellular targets, such as proteins or lipids 6.
• Invasive Agents: Drugs can interact with invasive agents, such as bacteria or viruses 6.