Верапамил химические свойства, назначение, производство
Использование
Verapamil is primarily used as an antiarrythmic for treating ventricular
arrhythmias; however, currently it is being forced out gradually by adenosine.
Определение
ChEBI: A tertiary amino compound that is 3,4-dimethoxyphenylethylamine in which the hydrogens attached to the nitrogen are replaced by a methyl group and a 4-cyano-4-(3,4-dimethoxyphenyl)-5-methylhexyl group.
Общее описание
Verapamil, 5-[. Hemodynamically, verapamil causesa change in the preload, afterload, contractility, heart rate,and coronary blood flow. The drug reduces systemic vascularresistance and mean blood pressure, with minor effectson cardiac output.
Verapamil is a synthetic compound possessing slightstructural similarity to papaverine. It can be separated intoits optically active isomers, of which the levorotatory enantiomeris the most potent. It is absorbed rapidly after oraladministration. The drug is metabolized quickly and, as aresult, has low bioavailability. The liver is the main siteof first-pass metabolism, forming several products. Thepreferential metabolic step involves N-dealkylation, followedby O-demethylation, and subsequent conjugation ofthe product before elimination. The metabolites have no significantbiological activity. Verapamil has an eliminationhalf-life of approximately 5 hours.
Механизм действия
Verapamil is used as an antiarrythmic drug in treating supraventricular arrythmia such as
paroxysmal atrial tachycardia, and for controlling atrial fibrillation. By blocking entrance
of Ca2+ in the cell, verapamil exhibits a negative inotropic effect, and therefore it cannot
be combined with β-adrenoblockers or cynidine since that would lead to an increased
inotropic effect.
Клиническое использование
Verapamil (Isoptin, Covera), in addition to its use as an
antiarrhythmic agent, has been employed extensively in
the management of variant (Prinzmetal’s) angina and
effort-induced angina pectoris. It selectively inhibits the voltage-gated calcium
channel that is vital for action potential genesis in slowresponse
myocytes, such as those found in the sinoatrial
and A-V nodes.
Verapamil is useful for slowing the ventricular response
to atrial tachyarrhythmias, such as atrial flutter and fibrillation.
Verapamil is also effective in arrhythmias supported
by enhanced automaticity, such as ectopic atrial
tachycardia and idiopathic left ventricular tachycardia.
Побочные эффекты
Orally administered verapamil is well tolerated by most
patients. Most complaints are of constipation and gastric
discomfort. Other complaints include vertigo,
headache, nervousness, and pruritus.
Меры предосторожности
Verapamil must be used with extreme caution or not at
all in patients who are receiving -adrenoceptor blocking
agents. Normally, the negative chronotropic effect of
verapamil will in part be overcome by an increase in reflex
sympathetic tone. The latter is be prevented by simultaneous
administration of a β-adrenoceptor blocking
agent, which exaggerates the depressant effects of verapamil on heart rate, A-V node conduction, and
myocardial contractility. The use of verapamil in children
less than 1 year of age is controversial.
Верапамил препаратная продукция и сырье
сырьё
препарат