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Loading Dose
In pharmacokinetics, a loading dose is an initial higher dose of a drug that may be given at the beginning of a course of treatment before dropping down to a lower maintenance dose. A loading dose is most useful for drugs that are eliminated from the body relatively slowly, i.e. have a long systemic half-life. Such drugs need only a low maintenance dose in order to keep the amount of the drug in the body at the appropriate therapeutic level, but this also means that, without an initial higher dose, it would take a long time for the amount of the drug in the body to reach that level. Drugs which may be started with an initial loading dose include digoxin, teicoplanin, voriconazole, procainamide and fulvestrant Fulvestrant, sold under the brand name Faslodex among others, is a medication used to treat hormone receptor (HR)-positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced br .... One or series ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacokinetics
Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs, pesticides, food additives, cosmetics, etc. It attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment that it is administered up to the point at which it is completely eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics (PD) is the study of how the drug affects the organism. Both together influence dosing, benefit, and adverse effects, as seen in PK/PD models. Overview Pharmacokinetics describes how the body affects a specific xenobiotic/chemical after administration through the mechanisms of absorption and distribution, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maintenance Dose
In pharmacokinetics, a maintenance dose is the maintenance rate g/hof drug administration equal to the rate of elimination at steady state. This is not to be confused with dose regimen, which is a type of drug therapy in which the dose gof a drug is given at a regular dosing interval on a repetitive basis. Continuing the maintenance dose for about 4 to 5 half-lives (t½) of the drug will approximate the steady state level. One or more doses higher than the maintenance dose can be given together at the beginning of therapy with a loading dose. A loading dose is most useful for drugs that are eliminated from the body relatively slowly. Such drugs need only a low maintenance dose in order to keep the amount of the drug in the body at the appropriate level, but this also means that, without an initial higher dose, it would take a long time for the amount of the drug in the body to reach that level. Calculating the maintenance dose The required maintenance dose may be calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemic Effect
An adverse drug reaction (ADR) is a harmful, unintended result caused by taking medication. ADRs may occur following a single dose or prolonged administration of a drug or result from the combination of two or more drugs. The meaning of this term differs from the term "side effect" because side effects can be beneficial as well as detrimental. The study of ADRs is the concern of the field known as ''pharmacovigilance''. An adverse drug event (ADE) refers to any unexpected and inappropriate occurrence at the time a drug is used, whether or not associated with the administration of the drug. An ADR is a special type of ADE in which a causative relationship can be shown. ADRs are only one type of medication-related harm, as harm can also be caused by omitting to take indicated medications. Classification ADRs may be classified by e.g. cause and severity. Cause *Type A: Augmented pharmacologic effects - dose dependent and predictable :Type A reactions, which constitute approximate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half-life
Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay. For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body. The converse of half-life (in exponential growth) is doubling time. The original term, ''half-life period'', dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to ''half-life'' in the early 1950s. Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Therapeutic Index
The therapeutic index (TI; also referred to as therapeutic ratio) is a quantitative measurement of the relative safety of a drug. It is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity. The related terms therapeutic window or safety window refer to a range of doses which optimize between efficacy and toxicity, achieving the greatest therapeutic benefit without resulting in unacceptable side-effects or toxicity. Classically, in an established clinical indication setting of an approved drug, TI refers to the ratio of the dose of drug that causes adverse effects at an incidence/severity not compatible with the targeted indication (e.g. toxic dose in 50% of subjects, TD) to the dose that leads to the desired pharmacological effect (e.g. efficacious dose in 50% of subjects, ED). In contrast, in a drug development setting TI is calculated based on plasma exposure levels. In the early days of pharmaceutical toxico ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digoxin
Digoxin (better known as Digitalis), sold under the brand name Lanoxin among others, is a medication used to treat various heart conditions. Most frequently it is used for atrial fibrillation, atrial flutter, and heart failure. Digoxin is one of the oldest medications used in the field of cardiology. It works by increasing myocardial contractility, increasing stroke volume and blood pressure, reducing heart rate, and somewhat extending the time frame of the contraction. Digoxin is taken by mouth or by injection into a vein. Digoxin has a half life of approximately 36 hours given at average doses in patients with normal renal function. It is excreted mostly unchanged in the urine. Common side effects include breast enlargement with other side effects generally due to an excessive dose. These side effects may include loss of appetite, nausea, trouble seeing, confusion, and an irregular heartbeat. Greater care is required in older people and those with poor kidney function. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teicoplanin
Teicoplanin is an antibiotic used in the prophylaxis and treatment of serious infections caused by Gram-positive bacteria, including methicillin-resistant ''Staphylococcus aureus'' and ''Enterococcus faecalis''. It is a semisynthetic glycopeptide antibiotic with a spectrum of activity similar to vancomycin. Its mechanism of action is to inhibit bacterial cell wall synthesis. Teicoplanin is marketed by Sanofi-Aventis under the trade name Targocid. Other trade names include Ticocin marketed by Cipla(India). Oral teicoplanin has been demonstrated to be effective in the treatment of pseudomembranous colitis and '' Clostridium difficile''-associated diarrhoea, with comparable efficacy with vancomycin. Its strength is considered to be due to the length of the hydrocarbon chain. Teicoplanin is produced by so-called "rare" actinobacterium ''Actinoplanes teichomyceticus'' ATCC 31121, belonging to the ''Micromonosporaceae'' family. Biosynthetic pathway leading to teicoplanin, as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voriconazole
Voriconazole, sold under the brand name Vfend among others, is an antifungal medication used to treat a number of fungal infections. This includes aspergillosis, candidiasis, coccidioidomycosis, histoplasmosis, penicilliosis, and infections by ''Scedosporium'' or ''Fusarium''. It can be taken by mouth or used by injection into a vein. Common side effects include vision problems, nausea, abdominal pain, rash, headache, and seeing or hearing things that are not present. Use during pregnancy may result in harm to the baby. It is in the triazole family of medications. It works by affecting fungal metabolism and fungal cell membranes. Voriconazole was patented in 1990 and approved for medical use in the United States in 2002. It is on the World Health Organization's List of Essential Medicines. Medical uses Voriconazole is used to treat invasive aspergillosis and candidiasis and fungal infections caused by ''Scedosporium'' and ''Fusarium'' species, which may occur in immunocomprom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procainamide
Procainamide (PCA) is a medication of the antiarrhythmic class used for the treatment of cardiac arrhythmias. It is classified by the Vaughan Williams classification system as class Ia; thus it is a sodium channel blocker of cardiomyocytes. In addition to blocking the ''I''Na current, it inhibits the ''I''Kr rectifier K+ current. Procainamide is also known to induce a voltage-dependent open channel block on the batrachotoxin (BTX)-activated sodium channels in cardiomyocytes. Uses Medical Procainamide is used for treating ventricular arrhythmias: ventricular ectopy and tachycardia and supraventricular arrhythmias: atrial fibrillation, and re-entrant and automatic supraventricular tachycardia. For example, it can be used to convert new-onset atrial fibrillation, and although was initially thought to be suboptimal for this purpose, a growing body of literature is amounting in support for this exact cause. It is administered by mouth, by intramuscular injection, or intravenously. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulvestrant
Fulvestrant, sold under the brand name Faslodex among others, is a medication used to treat hormone receptor (HR)-positive metastatic breast cancer in postmenopausal women with disease progression as well as HR-positive, HER2-negative advanced breast cancer in combination with palbociclib in women with disease progression after endocrine therapy. It is given by injection into a muscle. Fulvestrant is a selective estrogen receptor degrader (SERD) and was first-in-class to be approved. It works by binding to the estrogen receptor and destabilizing it, causing the cell's normal protein degradation processes to destroy it. Fulvestrant was approved for medical use in the United States in 2002. Medical uses Breast cancer Fulvestrant is used for the treatment of hormone receptor positive metastatic breast cancer or locally advanced unresectable disease in postmenopausal women; it is given by injection. A 2017 Cochrane review found it is as safe and effective as first line or second li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Half-life
Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the blood plasma, and is denoted by the abbreviation t_. This is used to measure the removal of things such as metabolites, drugs, and signalling molecules from the body. Typically, the biological half-life refers to the body's natural cleansing through the function of the liver and through the excretion of the measured substance through the kidneys and intestines. This concept is used when the rate of removal is roughly exponential. In a medical context, half-life explicitly describes the time it takes for the blood plasma concentration of a substance to halve (''plasma half-life'') its steady-state when circulating in the full blood of an organism. This measurement is useful in medicine, pharmacology and pharmacokinetics because it helps det ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', ''number concentration'', and ''volume concentration''. The concentration can refer to any kind of chemical mixture, but most frequently refers to solutes and solvents in solutions. The molar (amount) concentration has variants, such as normal concentration and osmotic concentration. Etymology The term concentration comes from the word concentrate, from the French , from con– + center, meaning “to put at the center”. Qualitative description Often in informal, non-technical language, concentration is described in a qualitative way, through the use of adjectives such as "dilute" for solutions of relatively low concentration and "concentrated" for solutions of relatively high concentration. To concentrate a solution, one must add more solute (for example, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
