Vitamin K Antagonists

Vitamin K antagonists (VKAs) are oral anticoagulant medicines that reduce the blood’s ability to form clots, making them important in clinical prevention and treatment of thromboembolic disease. They inhibit vitamin K epoxide reductase, limiting regeneration of active vitamin K and thereby impairing gamma-carboxylation of vitamin K–dependent coagulation proteins, including factors II, VII, IX, and X and proteins C and S. Because their effect develops and wears off gradually and varies with diet, medications, liver function, and genetics, treatment commonly requires dose adjustment and international normalized ratio (INR) monitoring; careful management helps balance protection from thrombosis against bleeding risk.

Vitamin K Antagonists - Related Videos

Education

JoVE Core - Pharmacology

Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants

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2024

Oral anticoagulants are vital tools in preventing and treating blood clotting disorders. This diverse class of medications can be categorized as vitamin K antagonists, exemplified by warfarin, and direct thrombin inhibitors (DTIs), such as dabigatran, as well as factor Xa inhibitors, including rivaroxaban. Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...

Research

JoVE Journal - Bioengineering
Free Sample

PLGA Nanoparticles Formed by Single- or Double-emulsion with Vitamin E-TPGS

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Cited by 211 •

2013

We describe the production and characterization of nanoparticles and microparticles composed of poly(lactic-co-glycolic acid) using vitamin E-TPGS as an emulsifier. By varying formulation parameters such as the concentration of emulsifier, it is possible to produce nanoparticles with mean diameters ranging from 220 nm to 1.98 µm.

Vitamins

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2024

Vitamins, derived from the Latin word for life, are essential organic substances required in small quantities for optimal growth and overall well-being. Unlike other organic nutrients, vitamins don't act as sources of energy or building materials but rather facilitate these nutrients' utilization by the body. Vitamins are predominantly coenzymes, assisting enzymes in specific chemical actions, like the oxidation of glucose for energy involving B vitamins. Most vitamins are not produced in our...

Cholinergic Antagonists: Pharmacokinetics

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2023

Cholinergic antagonists—such as antimuscarinics—are available in oral, topical, ocular, parenteral, and inhalational formulations. Most antimuscarinics are oral formulations, while scopolamine is available as a topical patch, and ipratropium and tiotropium are available as inhalation aerosols or powders. Atropine, tropicamide, and cyclopentolate are topically instilled in the eye. Most antimuscarinics are lipid-soluble and readily absorbed from the gastrointestinal tract and the conjunctiva.

Cholinergic Antagonists: Therapeutic Uses

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2023

Antimuscarinic drugs have various therapeutic applications by inhibiting parasympathetic stimulation in different systems. Here are the key therapeutic uses of antimuscarinics: Respiratory Tract: Ipratropium, aclidinium, and tiotropium treat asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). They protect against bronchoconstriction caused by irritants like cigarette smoke, sulfur dioxide, and ozone. They also help reduce nasopharyngeal secretions in common...

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