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antiarrhythmic, antihypertensive - Coggle Diagram
antiarrhythmic
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drug interactions
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amiodarone
may increase warfin, digoxin, xyxlosporine, alprazolam, carbamazepine, simvastatin, phenytoin, quinidine
side effects
possible issues with your liver, kidneys, thyroid or lungs
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shortness of breath
(if this gets so bad that you feel unsafe, seek medical attention immediately).
mechanism of action
All antiarrhythmic drugs directly or indirectly alter membrane ion conductances, which in turn alters the physical characteristics of cardiac action potentials.
some drugs are used to block fast sodium channels. These channels determine how fast the membrane depolarizes (phase 0) during an action potential. Since conduction velocity is related to how fast the membrane depolarizes, sodium channel blockers reduce conduction velocity. Decreasing conduction velocity can help to abolish tachyarrhythmias caused by reentry circuits
contradiction
Patients with severe sinus-node dysfunction, causing marked sinus bradycardia; second- and third-degree atrioventricular block; and when episodes of bradycardia have caused syncope (except when used in conjunction with a pacemaker). Patients with a known hypersensitivity to the drug
pharmacologic effects
Antiarrhythmic drugs are used to: decrease or increase conduction velocity. alter the excitability of cardiac cells by changing the duration of the effective refractory period. suppress abnormal automaticity.
major adverse reactions
possible issues with your liver, kidneys, thyroid or lungs
pharmacokinetics
Antiarrhythmic agents act by blocking the membrane sodium, potassium, and calcium channels, but no agent has exclusive action on a given type of channel. Arrhythmias resulting from reentry form the largest group of clinically significant arrhythmias. Most arrhythmias result from depressed sodium channel function.
antihypertensive
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contradictions
Compelling contraindications are pregnancy, bilateral renal artery stenosis and hyperkalaemia. Angiotensin-II antagonists are the newest of the first- choice antihypertensive agents.
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drug examples
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amlodipine besylate (Norvasc), a calcium channel blocker
ACE inhibitor lisinopril (Prinivil, Zestril)
drug interactions
Interactions between drugs and antihypertensive agents can result in either increased or decreased antihypertensive effects. These interactions may be pharmacokinetic or pharmacodynamic in type, resulting in either altered plasma drug concentrations or altered drug effects at similar plasma concentrations.
Pharmacokinetic interactions may result from alter- ations in drug absorption, drug distribution, drug me- tabolism, or drug excretion by nonmetabolic routes. Alteration of drug delivery to the systemic circulation
may occur because of a reduction in the drug's absorp- tion from the gastrointestinal tract following oral ad- ministration.
mechanism of action
The pathophysiology of hypertension involves the impairment of renal pressure natriuresis, the feedback system in which high blood pressure induces an increase in sodium and water excretion by the kidney that leads to a reduction of the blood pressure.
pharmacologic effects
Centrally-acting antihypertensives decrease blood pressure by diminishing sympathetic outflow from the vasomotor centre. Peripherally-acting antihypertensives act by depleting or inhibiting the release of catecholamines from the peripheral nerve ending or altering the response at alpha 1- and alpha 2-receptor sites.
pharmacokinetics
Does hypertension affect pharmacokinetics?
Interactions between drugs and antihypertensive agents can result in either increased or decreased antihypertensive effects. These interactions may be pharmacokinetic or pharmacodynamic in type, resulting in either altered plasma drug concentrations or altered drug effects at similar plasma concentrations.