Apparent volume of distribution formula

Lipid-soluble drugs are stored in fat. Bone is a reservoir for drugs such as tetracycline and heavy metals. The figure below shows values of Vd for different drugs click on the image to visualise an enlarged version :. Variation of Vd mainly affects the peak plasma concentration of the drug. This is important when peak plasma concentration is essential for the therapeutic effect e.

Volume of distribution - Wikipedia

Drug dosage must be adapted to the Vd for such drugs. Vd varies with individual height and weight. The most important causes of variation of Vd are accumulation of fat for lipid-soluble drugs such as for obese patients, or accumulation of fluids for water-soluble drugs such as ascites, edema or pleural effusion. As the proportion of each body compartment varies with age, so does the Vd for most drugs. Most importantly, the Vd is determined in conditions under which the drug distribution between the plasma and the tissues is at equilibrium. The Vd is commonly determined as shown below, after injection as an iv bolus. As can be appreciated from the description of the distribution and elimination phases see corresponding figure , the distribution of the drug between the plasma and the tissues is at an equilibrium, when the elimination phase is reached. PMID Cambridge MedChem Consulting. Retrieved Antagonist Competitive antagonist Irreversible antagonist Physiological antagonist Inverse agonist Enzyme inhibitor.

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1.3: Pharmacokinetics I

Pharmacotoxicology Neurotoxicology. Classical pharmacology Reverse pharmacology. Photopharmacology Immunopharmacology Cell biology Physiology. Drug tolerance Tachyphylaxis Drug resistance Antibiotic resistance Multiple drug resistance. Antimicrobial pharmacodynamics Minimum inhibitory concentration Bacteriostatic Minimum bactericidal concentration Bactericide. Category : Pharmacokinetics. Hidden categories: Articles with short description Short description is different from Wikidata Pages that use a deprecated format of the math tags. Toggle limited content width. Theophylline , Ethanol. Shows highly lipophilic molecules which sequester into total body fat. Highly charged hydrophilic molecule. Design parameter. Dosing interval. Maximum serum concentration. Direct measurement. Minimum time for Cmax.

“Fluid volume that would be required to contain the amount of drug present in the body at the same concentration as in the plasma”

Minimum plasma concentration. The lowest trough concentration that a drug reaches before the next dose is administered. The average plasma concentration of a drug over the dosing interval in steady state. The apparent volume in which a drug is distributed i. Amount of drug in a given volume of plasma. Absorption half-life. Absorption rate constant. Elimination rate constant.

Introduction to Distribution - Chemistry LibreTexts

Area under the curve. The integral of the concentration-time curve after a single dose or in steady state. Activity at receptor Mechanism of action Mode of action Binding Receptor biochemistry Desensitization pharmacology.