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Mexiletine
Mexiletine (INN) (sold under the brand names Mexitil and Namuscla) is a medication used to treat abnormal heart rhythms, chronic pain, and some causes of muscle stiffness. Common side effects include abdominal pain, chest discomfort, drowsiness, headache, and nausea. It works as a non-selective voltage-gated sodium channel blocker and belongs to the Class IB group of anti-arrhythmic medications. Medical uses Mexiletine has several uses including the treatment of abnormal heart rhythms or arrhythmias, chronic pain, and myotonia. In general when treating arrhythmias, mexiletine is reserved for use in dangerous heart rhythm disturbances such as ventricular tachycardia. It is of particular use when treating arrhythmias caused by long QT syndrome. The LQT3 form of long QT syndrome is amenable to treatment with mexiletine as this form is caused by defective sodium channels that continue to release a sustained current rather than fully inactivating, however other forms of long QT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexiletine Synthesis
Mexiletine (INN) (sold under the brand names Mexitil and Namuscla) is a medication used to treat abnormal heart rhythms, chronic pain, and some causes of muscle stiffness. Common side effects include abdominal pain, chest discomfort, drowsiness, headache, and nausea. It works as a non-selective voltage-gated sodium channel blocker and belongs to the Class IB group of anti-arrhythmic medications. Medical uses Mexiletine has several uses including the treatment of abnormal heart rhythms or arrhythmias, chronic pain, and myotonia. In general when treating arrhythmias, mexiletine is reserved for use in dangerous heart rhythm disturbances such as ventricular tachycardia. It is of particular use when treating arrhythmias caused by long QT syndrome. The LQT3 form of long QT syndrome is amenable to treatment with mexiletine as this form is caused by defective sodium channels that continue to release a sustained current rather than fully inactivating, however other forms of long QT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP1A2
Cytochrome P450 1A2 (abbreviated CYP1A2), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the human body. In humans, the CYP1A2 enzyme is encoded by the ''CYP1A2'' gene. Function CYP1A2 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP1A2 localizes to the endoplasmic reticulum and its expression is induced by some polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke. The enzyme's endogenous substrate is unknown; however, it is able to metabolize some PAHs to carcinogenic intermediates. Other xenobiotic substrates for this enzyme include caffeine, aflatoxin B1, and paracetamol (acetaminophen). The transcript from this gene contains four Alu sequences flanked by direct repeats in the 3' untranslated region. CYP1A2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myotonia Congenita
Myotonia congenita is a congenital neuromuscular channelopathy that affects skeletal muscles (muscles used for movement). It is a genetic disorder. The hallmark of the disease is the failure of initiated contraction to terminate, often referred to as delayed relaxation of the muscles (myotonia) and rigidity. Symptoms include delayed relaxation of the muscles after voluntary contraction (myotonia), and may also include stiffness, hypertrophy (enlargement), transient weakness in some forms of the disorder (from certain genetic mutations), severe masseter spasm, and cramping. The condition is sometimes referred to as fainting goat syndrome, as it is responsible for the eponymous 'fainting' seen in fainting goats when presented with a sudden stimulus. Of note, myotonia congenita has no association with malignant hyperthermia (MH). Symptoms and signs The prolonged muscle contractions, which occur most commonly in the leg muscles in recessive mutations, and more commonly in the hands, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Channel Blocker
Sodium channel blockers are drugs which impair the conduction of sodium ions (Na+) through sodium channels. Extracellular The following naturally-produced substances block sodium channels by binding to and occluding the extracellular pore opening of the channel: * Alkaloids: ** Saxitoxin (STX) ** Neosaxitoxin (NSTX) ** Tetrodotoxin (TTX) Intracellular Drugs which block sodium channels by blocking from the intracellular side of the channel include: * Local anesthetics: ''lidocaine'' * Class I antiarrhythmic agents * Various anticonvulsants: ''phenytoin, oxcarbazepine (derivative of carbamazepine)'' Unknown mechanism * Calcium has been shown to block sodium channels which explains the effects of hypercalcemia and hypocalcemia. * Lamotrigine is known to block sodium channels but it is not known whether it is extracellular or intracellular. * Cannabidiol (CBD) has been shown to cause inhibitory effects on sodium currents. This voltage-dependent inhibition is non-selective in nature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analgesics
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It is typically used to induce cooperation with a medical procedure. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in some instances eliminate, sensation, although analgesia and anesthesia are neurophysiologically overlapping and thus various drugs have both analgesic and anesthetic effects. Analgesic choice is also determined by the type of pain: For neuropathic pain, traditional analgesics are less effective, and there is often benefit from classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants. Various analgesics, such as many NSAIDs, are available over the counter in most countries, whereas various others are prescription drugs owing to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP2D6
Cytochrome P450 2D6 (CYP2D6) is an enzyme that in humans is encoded by the ''CYP2D6'' gene. ''CYP2D6'' is primarily expressed in the liver. It is also highly expressed in areas of the central nervous system, including the substantia nigra. CYP2D6, a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. In particular, CYP2D6 is responsible for the metabolism and elimination of approximately 25% of clinically used drugs, via the addition or removal of certain functional groups – specifically, hydroxylation, demethylation, and dealkylation. CYP2D6 also activates some prodrugs. This enzyme also metabolizes several endogenous substances, such as hydroxytryptamines, neurosteroids, and both ''m''-tyramine and ''p''-tyramine which CYP2D6 metabolizes into dopamine in the brain and liver. Considerable variation exists in the efficiency and amount of CYP2D6 enzyme produced betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myotonic Dystrophy
Myotonic dystrophy (DM) is a type of muscular dystrophy, a group of genetic disorders that cause progressive muscle loss and weakness. In DM, muscles are often unable to relax after contraction. Other manifestations may include cataracts, intellectual disability and heart conduction problems. In men, there may be early balding and an inability to have children. While myotonic dystrophy can occur at any age, onset is typically in the 20s and 30s. Myotonic dystrophy is caused by a genetic mutation in one of two genes. Mutation of the '' DMPK'' gene causes myotonic dystrophy type 1 (DM1). Mutation of '' CNBP'' gene causes type 2 (DM2). DM is typically inherited from a person's parents, following an autosomal dominant inheritance pattern, and it generally worsens with each generation. A type of DM1 may be apparent at birth. DM2 is generally milder. Diagnosis is confirmed by genetic testing. There is no cure. Treatments may include braces or wheelchairs, pacemakers and non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it is located in the quadrant (anatomy), right upper quadrant of the abdomen, below the thoracic diaphragm, diaphragm. Its other roles in metabolism include the regulation of Glycogen, glycogen storage, decomposition of red blood cells, and the production of hormones. The liver is an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which helps the fatty acid degradation, breakdown of fat. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver which is later moved to the small intestine to complete digestion. The liver's highly specialized biological tissue, tissue, consisting mostly of hepatocytes, regulates a w ... [...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] |
Renal Impairment
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as either acute kidney failure, which develops rapidly and may resolve; and chronic kidney failure, which develops slowly and can often be irreversible. Symptoms may include leg swelling, feeling tired, vomiting, loss of appetite, and confusion. Complications of acute and chronic failure include uremia, high blood potassium, and volume overload. Complications of chronic failure also include heart disease, high blood pressure, and anemia. Causes of acute kidney failure include low blood pressure, blockage of the urinary tract, certain medications, muscle breakdown, and hemolytic uremic syndrome. Causes of chronic kidney failure include diabetes, high blood pressure, nephrotic syndrome, and polycystic kidney disease. Diagnosis of acute failure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Racemic Mixture
In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. History The first known racemic mixture was racemic acid, which Louis Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid. He manually separated the crystals of a mixture by hand, starting from an aqueous solution of the sodium ammonium salt of racemate tartaric acid. Pasteur benefited from the fact that ammonium tartrate salt that gives enantiomeric crystals with distinct crystal forms (at 77 °F). Reasoning from the macroscopic scale down to the molecular, he reckoned that the molecules had to have non-superimposable mirror images. A sample with only a single enantiomer is an ''enantiomerically pure'' or ''enantiopure'' compound. Etymology From racemic acid found in grapes; from Latin ''racemus'', meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creatinine Clearance
Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging. Functions of a healthy kidney include maintaining a person's fluid balance, maintaining an acid-base balance; regulating electrolytes including sodium, potassium, and other electrolytes; clearing toxins; regulating blood pressure; and regulating hormones, such as erythropoietin; and activation of vitamin D. Introduction The functions of the kidney include maintenance of acid-base balance; regulation of fluid balance; regulation of sodium, potassium, and other electrolytes; clearance of toxins; absorption of glucose, amino acids, and other small molecules; regulation of blood pressure; production of various hormones, such as erythropoietin; and activation of vitamin D. Much of renal physiology is studied at the level of the nephron, the smallest functional unit of the kidney. Each nephron begins w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
