Angina control drugs and drugs for treatment following an MI Flashcards
What is the function of Nitroc oxide (NO)
It is an endothelium-derived relaxing factor
It causes:
Venous vasodilation /pre-‐load reduction
Arterial dilation /after-‐load reduction
Coronary artery vasodilation
Prevention of coronary vasoconstriction
Enhancement of coronary collateral flow
Antiplatelet and antithrombotic effects
What is the mechanism of action of nitrates
Increase the production of NO from the endothelium
They are metabolized to increase NO
1) NO stimulates guanylate cyclase
2) Gaunylate cyclase synthesizes cGMP
3) cGMP activates cCGMP –dependent protein kinase
4) cGMPdK activates myosin light chain phosphate(s) (MLCP)
5) Myosin light chains in the smooth muscle cells are dephosphorylated.
6) The contractile state of the smooth muscles
depends on phosphorylation of the myosin light chains (calmodulin-‐dependent kinase phosphorylates)
Give examples of nitrates used to treat angina
Nitroglycerin (fast acting) Isosorbide mononitrate Isosorbide dinitrate Transdermal patches (long acting) Alkyl Nitrates (poppers)
What are the side effects of the nitrates
Headach Flushing Palpatations Tolerance Major interaction with viagra leading to hypotensive crisis
Give examples of beta-blockers used to treat angina
Propanalol
Atenolol
Carvedilol
What is the function of beta-blockers
They reduce myocardial oxygen demand
What is the mechanism of action of propanolol
non-selective Beta1 and Beta2 adrenoreceptor blocker
what is the mechanism of action of atenolol
more beta-1 selective blocker
what is the mechanism of action of Carvedilol
Beta blocker and also blocks alpha-adrenoreceptors imprvign coronary perfusion
When are beta-blockers used
first-‐line therapy in the treatment of chronic stable angina (esp. effort-‐induced angina)
What are the side effects of the beta-blockers
constipation indigestion hypotension sleep disturbances hallucinations (rare) reduce aqueous humor secretion (good for treating glaucoma) skin reactions e.g. hives, psoriasis
Give examples of Ca2+ channel blockers used in the treatment of angina
Dihyropyridines e.g. Nifedipine
Phenylalkylamines e.g. Verapamil
Benzothiazepine e.g. Diltiazem
(also non-‐selective VDCC blockers e.g. Fluspiriline)
What is the mechanism of action of the Ca2+ channel blockers
Ca2+ entry to Smooth Muscle depends on
activity of voltage dependent Ca2+ channels
(mainly L-‐type Voltage Dependant Calcium Channels)
They are L-‐type VDCC antagonists
What are the side effects of the Ca2+ channel blockers
Peripheral vasodilation: dizziness, headachs, erythema
constipation
heart rate changes
Gingival overgrowth
What are Phenylalkylamines e.g. Verapamil
selective for
myocardium hence they have minimal peripheral vasodilatory effects (compared with Dihyropyridines)
What are Benzothiazepine e.g. Diltiazem good for
Having both cardiac depressant and
vasodilator actions, benzothiazepines are
able to reduce arterial pressure without producing as much reflex cardiac stimulation
caused by dihydropyridines.
Give an example of an antiplatelet drug used to treat angina
Clopidogrel
What is the mechanism of Clopidogrel
It is a pro-drug which blocks the ADP receptor on the platelet membrane preventing platelet aggregation and clot formation
What are the side effects of Clopidogrel
Haemorrhage
Severe neutropenia
Thrombotic thrombocytopenic purpura (paradoxical)
What is the mechanism of action of asprin
It is synthesized to salicylate
It inhibits thromboxane A2 production by inhibiting COX
It thus has an antiplatelet effect
What is asprin used for at low doses
Help prevent heart attacks (may be given immediatly after heart attack to reduce the risk of a second heart attack)
Help prevent strokes
Help prevent bood clots
What are the side effects of asprin
GI ulcers/ bleeding
Tinnitus
What is used to minimize cardiac dysfunction following ischemia
Ranolazine
what is the mechanism of action of Ranolazine
It blocks late Na+ entry reducing cardiac dysfunction by:
Increasing the QT interval
What does ranolazine decrease
It decreases angina episodes in individuals with coronary artery disease on maximal doses of amlodipine and exercise tolerance in those taking atenolol, amlodipine or diltiazem
What are the side effects of Ranolazine
Worsen electrical dysfunction in long-OT syndrome which could lead to sudden cardiac death
