Mild hypertension use weight control avoid salt

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Unformatted text preview: ion • Useful in Black patients – Mechanism of action - prevents hypervolemia • Initially decreases blood volume and fluid in tissues – Causes increased Na+ excretion and water follows • appears to also relax blood vessels – Side or toxic effects • potassium depletion (causes arrhythmias) • may aggravate diabetes mellitus – thiazides seem to inhibit insulin secretion – Contraindications or Cautions • possibly diabetes • renal or liver disease (somehow thiazides aggravate condition) • cardiac arrhythmias (because of K+ depletion) Summary of Antihypertensive Drugs Summary • Control of hypertension difficult – all effective agents produce significant side effects. – Mild hypertension use - weight control, avoid salt, possibly exercise. – When drug therapy required, usually use 2 or more drugs - helps avoid side effects. • hydralazine (relaxes vessels directly but causes reflex tachycardia) with propranolol (β blocker - lower B.P. and also reduces tachycardia) • or a diuretic with any other kind of agent. Hypertensive emergencies Hypertensive • Classically Use I.V. medicines that relax blood vessels • Diazoxide (Hyperstat®) - given I.V. push or drip- used with a diuretic, relaxes arteries and venules possibly by antagonizing Ca++ • Sodium Nitroprusside (Nipride®) - I.V. drip - requires constant attention - relaxes arteries and venules • Labetolol IV (alpha and beta blocker)- easily countered with specific antidotes, can be followed with oral form. • Oral Agents Becoming Popular • Clonidine - central sympathetic blockade- takes 30-60 minutes to lower BP. Used in office. • Nifedipine capsule - calcium channel blocker- break open and put under tongue. Onset in seconds. BP near normal in 30 minutes. • Captopril - ACE Inhibitor (RAA). Many emergencies are due to an overactive renin-angiotensin system. This agent works in minutes. Antihypotensive Agents Antihypotensive • Mechanism of Action - to increase BP by: – Increased peripheral resistance α agonist • phenylephrine (for spinal anesthesia) or dopamine – Increased cardiac output -beta agonists • isoproterenol (a β agonist - for shock) – *Sometimes use drugs that are both alpha & beta agonists, eg. ephedrine (for...
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This document was uploaded on 02/07/2014.

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