Pharmacology of the heart and cardiovascular system
Pharmacology of the heart
High mortality due to the cardiovascular diseases leads to high interest to treat it
Except primary prevention (healthy life style, motion, low-energy food…) is necessary also a good and sufficient therapy and so called secondary prevention, i.e. early therapy of cardiovascular disease and prevention of the complications.
Development of the new drugs for this area is really large and every year comes minimally 10 – 20 new products – drugs.
Effects of cardiovascular drugs:
To quality of the hearth muscle – contractility, inothropy
To the hearth rhythmus and frequency – against arhytmias
To the metabolism of the myocard and the quality of the supplementation of the heart with the blood. (Low flow of blood in the coronary arteries is causing f.ex. angina pectoris.
Function of the heart as a pump
Necessary is presence of the Ca2+ in the cells for myocard-contraction
Drugs, which are increasing the concentration of the Ca2+ in the cells are increasing the contractility of the myocard (Cardiac failure)
They are called cardiotonics (according to the function)or cardioglykosids( according to the chemical structure)
They block Na+K+ATPas in the celular membrane of the myocardial cells and so the slow down exchange of Ca2+ and Na+. Intracelular Ca2+concentration increases and myocard contract more powerful
They slow down the rhythmus and conduction on the cardiac conduction pathway and may lead to the arhytmias, but on the other hand is used to therapy of some arhytmias – atrial fibrillation.
Side effects: vomiting, dizziness, yellow colored vision, disorientation
Low concentration of K+ in the blood can lead to easy overdosing, higher to the toxicity and therefore it is necessary to monitorate the level of the cardioglykosids in plasma
Digoxin, Digoxin, Lanacrist, Lanoxin (p.o., i.v.)
Medigoxin: Lanitop (p.o.)
Digitoxin: Digitrin (p.o.)
Oubain: Strophantin G (i.v.)
New cardiotonics, which effect is due to the inhibition of phosphodiestherase we use in the failing of the classics therapy
Amrinon: Inocor, Milrinon :Corotrop (i.v.)
2. Antiarhytmics, antidysrhytmics The complex of mistakes in the cardiac conduction pathway (SA, AV., Hiss, LBB, RBB, and Purkynje f.) causes arrhythmia
Through peripheral resistance decrease, myocardial frequence AV conduction
Centrally acting antihypertensives
Acting directly in the CNS by decreasing the tonus of the symphaticus
Klonidin – Catapressan, Haemiton
Guanfacin - Estulic
Urapidil - Ebrantil
for serious types of hypertension
doxazosiln – Alfadil
Drugs effecting the muscular layer of the capillary wall
For serious types of hypertension
Minoxidil – Loniten
Natrium nitroprusid – Nipride
Drugs effecting sympaticus and parasympaticus Autonomic (vegetative) nerve system is participating importantly on the regulation organism´s functions, which are out of the voluntary control.
Schema of the system:
Drugs, which are effecting those systems, are called:
Parasympatomimetic d.– cholinergica
Parasympatholytic d.– anticholinergica
Activation of the adrenergic receptors
Directly or by releasing NADR from the postganglionic neuron
Basically the effect is called alpha () and beta ().
1 effect: vasoconstriction, mydriasis
2 effect: releasing of NADR lead to the decrease of production of cAMP and thus to decrease of NADR relief, so it is a control mechanism