1 - Antihypertensives Flashcards
What are the categories of hypertension and what’s involved in each category?
- Essential Hypertension (Primary or Idiopathic)
- 85-90% of all cases
- Secondary Hypertension
- Endocrine or renal system disease
- Drugs - NSAIDS, birth control, decongestants, tricyclic antidepressents
- Malignant Hypertension
- BP very high or rapidly rises
- Retinal and renal damage
What are the blood pressure guidelines?
- Normal <120 / <80
- Prehyptertension 120-139 / 80-89
- Stage 1 hypertension 140-159 / 90-99
- Stage 2 hypertension 160+ / 100+
What are the 3 basic methods used to obtain the overall goal of decreasing blood pressure?
- Reduce peripheral resistance
- Reduce cardiac output
- Decrease blood volume
How do diuretics work?
- Increase the rate of urine formation
- Most block the kidney tubular reabsorption of Na+
- Most diuretics are excreted by kidney tubular secretion
What are the major classes of diuretics?
- Thiazides
- Loop
- Potassium sparing
What was the first class of diuretics, that are also not on the market anymore?
Mercurials
They all start with “mer…”
What is the first choice agent for hypertension and congestive heart failure?
Thiazides (Benzothiazides)
What are the most commonly prescribed diuretics?
Thiazides
What are the common preparations of a thiazide diuretics?
- “HCTZ” Hydrochlorothiazide (Microzide)
- Chlorothiazide (Diuril)
What are the adverse effects of thiazide diuretics?
- Hypokalemia - is sodium intake increases, the potassium loss is exacerbated
- Elevated cholesterol
- Hyperglycemia
- Sexyal dysfunction
Thiazides are not good for patients with _________ or patients with __________ or lipids.
- Diabetes (elevated glucose)
- High cholesterol
What type of diuretic causes a major loss of volume?
Loop Diuretics
What is the drug of choice (diuretic) for serious edema?
Loop (high Ceiling) Diuretic
Why are Loop Diuretics potentially toxic?
- Major rapid loss of sodium and potassium = serious electrolyte imbalances may result
All loop diuretics are _______ to some degree (causing hearing loss/deafness)?
Ototoxic
What are the common preparations of Loop Diuretics?
- Lasix (furosemide) - most common
- Edecrin (ethacrynic acid)
What is Lichenoid Drug Reaction?
White splotchey drug reaction observed with Thiazide and Loop Diuretics
What are Potassium-sparing Diuretics? And what are the common preparations?
They block the effect of aldosterone, and prevent the usual loss of K+
- spironolactone (Aldactone)
- triamterene (Dyrenium)
- eplerenone (Inspra)
What are the adverse effects of Potassium-sparing diuretics?
- Hyperkalemia
- Gynecomastia
What are Carbonic Anhydrase Inhibitors primarily used for?
- Glaucoma, and therapy for congestive heart failure
acetazolamide - Diamox - common prep
What diuretics are filtered but not reabsorbed, and used in emergencies when a decrease in blood volume is needed?
Osmotic Diuretics
What type of diuretic is used in emergency rooms to treat hypochloremic states or metabolic alkalosis?
Acidifying agents - Ammonium Chloride
How do Xanthines work?
- Inhibit ADH - increases bloodflow and decreases reabsorption of water in collecting duct
Rank the following diuretics by degree of potency (most to least):
Potassium Sparing
Carbonic Anhydrase inhibitors
Loop
Thiazides
- Loop
- Thiazides
- Carbonic anhydrase inhibitors
- Potassium-sparing
What are some dental considerations dealing with diuretics?
- Xerostomia
- Apthous stomatitis
- Lichenoid drug reaction
- Use of NSAIDS for >3 weeks can decrease effectiveness of diuretics
What can patients take to counter the loss of potassium while taking diuretics?
Potassium Salts -
The supplements have “K” in the name (K-Tab, Klor-Con)
How do Beta-blockers work?
- Decrease cardiac output
- Decrease renin secretion
- Reduce plasma volume and venous return
- Decrease sympathetic outflow from CNS
- Reduce peripheral resistance
How can you classify a beta-blocker by it’s name?
- Beta-blockers end in “…olol”
- A-M are Cardioselective
- N-Z are Non-cardioselective
- Exceptions to this rule are usually meds for glaucoma
What are the contraindications to beta-blockers?
- Congestive heart failure - already decreased cardiac outpute
- Asthma
- Heart block
- Diabetes
What blockers produce peripheral vasodilation in arterioles and venules, decreasing peripheral vascular resistance?
Alpha 1 - Blockers
What are alpha-1 blockers used for?
- To improve urination in men with enlarged prostate and those with bladder problems
- BPH
- Old men!
What are some common preparations of Alpha-1 blockers?
- End in “…osin”
- doxazosin (Cardura)
- prazosin (Minipress)
- *tamsulosin (Flomax) - teratogenic** with side effect of severe orthostatic hypotension
What drug prevents conversion of angiotensin I to angiotensin II (a potent vasoconstrictor)?
ACE inhibitors
What is the mechanism of action for ACE inhibitors?
- Decrease secretion of aldosterone which decreases sodium and water retention
- Vasodilation and decreased blood volume lower blood pressue
What are some common ACE inhibitors?
- End in “…pril”
- enalapril (Vasotec)
- lisinopril (Prinivil, Zestril) - biggest seller
- benzepril (lotensin)
- captopril (Capoten)
- fosinopril (Monopril)
What are some common side effects of ACE inhibitors?
- Chronic dry cough - mediated by increased bradykinin release in bronchial tree
- Angioneurotic edema with first dose - which is why the first dose should be taken at physicians office
What are ARBs?
Angiotensin Receptor Blockers
- Blocks vasoconstriction and aldosterone-secreting effects of angiotensin II
- Increase in plasma renin level causing vasodilation, decreased sodium and water retention
- Which leads to reduction in blood pressure
What are some common preparations of ARBs?
End in “…sartan”
- losartan (Cozaar)
- valsartan (Diovan)
- candesartan (Atacand)
What is a Renin Inhibitor?
A new drug class for hypertension
- Binds to renin which then reduces levels of angiotensin I, angiotensin II, and aldosterone
What are calcium channel blockers used for?
- Hypertension
- Angina
- Arrhythmias
What are the common preparations of Calcium Channel Blockers?
- verapamil (Calan) - major effect on heart
- nifedipine (Procardia) - blood vessels
- amlodipine (Norvasc) - #1 in US sales
What calcium channel blocker is associated with the greatest numner of cases of gingival hyperplasia?
nifedipine (Procardia)
What is an important alpha 2 agonist and what does it act on?
- clonidine (Catapres) - alpha2 agonist - decreases sympathetic outflow from CNS
- Xerostomia, parotid gland swelling, dysguesia
What type of drug blocks granular uptake and storage (depletion) of norepinephrine = decreases sympathetic activity due to a lack of neurotransmitter supply?
Catecholamine Release Blockers
What are the common preps and characteristics of Catecholamine Release Blockers?
- reserpine (Serpasil) - decreased BP via depletion of NE and dopamine, crosses BBB (schizophrenia treatment)
- guanethidine (Ismelin) - uncouples action potential from exocytotic release of the transmitter (blocks AP)
What are Catecholamine Release Blockers contraindicated in?
Patients with peptic ulcers (increased HCl secretion)
What is the safe cardiac dose of epinephrine?
0.04 mg - always take BP prior to injection of local anesthetics
Use of NSAIDS for longer than 3 weeks may decrease the effectiveness of some ________. ________ and __________?
- Diuretics
- Beta blockers
- ACE inhibitors
What are the common treatments for stage 1 hypertension?
- Thiazide diuretics for most
- May consider ACEI, ARB, BB, CCB
What are common treatments for stage 2 hypertension?
- 2 drug combination for most
- Thiazide diuretic with ACEI, ARB, BB, CCB
What are common drugs used for compelling indications of hypertension?
- Diuretics
- ACEI
- ARB
- BB
- CCB
