Pharm management of HTN II - Lee Flashcards
centrally acting alpha2 receptor agonists
- clonidine*
- guanabenz
- guanfacine
- methyldopa*
-trying to shift things to parasympathetic side –> decrease HR –> decrease venous return –> lower BP
peripherally acting alpha1 receptor blockers
- doxazosin*
- prazosin*
- terazosin
-blocking constriction leading to vasodilation –> decrease BP
peripherally acting beta receptor blockers (beta blockers)
- cardioselective (beta1 receptor blockers)
- nonselective (beta1 and beta2 receptor blockers)
Ca2+ channel blockers
- amiodipine
- felodipine
- isradipine
- nicardipine
- nifedipine
- nimodipine
- nitrendipine
clonidine
-alpha 2 receptor agonist
- reduces sympathetic outflow –> reduce BP by decreasing TPR, renal vascular resistance, HR and SV, and increasing parasympathetic tone**
- better than methyldopa at reducing HR/SV
- used for HTN and ADHD*
- not used with fluid retention/edema or with heart failure with reduced ejection fraction
- side effects of dry mouth, dizzy, constipated, orthostatic hypotension, GI issues, rebound HTN (with sudden discontinuation), CNS depressive effects of EtOH/barbiturates/sedatives
methyldopa
- alpha2 receptor agonist
- prodrug
- used during PREGNANCY**
lowers atrial pressure by:
- alpha-methylnorepinephrine –> replace NE (false neurotransmission)
- reduce sympathetic outflow by activating alpha 2 in brainstem
- reduction of plasma renin activity
- used for HTN during pregnancy**
- not used in hepatic disease (hepatitis, cirrhosis)**
- risks of transient sedation, depression, hepatotoxicity*, hemolytic anemia**
prazosin
- alpha1 receptor antagonist*
- relaxes smooth muscle and blood vessels
- hypotension not accompanied by reflexive tachycardia
-orally, short half life (2-3 hr) –> take multiple doses each day
- indications: HTN
- contraindications: sensitivity to quinazolines and prazosin*
risk of orthostatic hypotension, nasal congestion, fluid retention*
doxazosin
- alpha1 receptor antagonist*
- long half life (22 hr) –> once a day dosing**
indications: benign prostate hyperplasia (BPH)**, HTN
contraindications: hypersensitivity to doxazosin and other quinazolines
risk of palpitation, headache, lassitude (lack energy)*
phenoxybenzamine
- alpha1 receptor antagonist* (long acting, nonselective, noncompetitive)*
- binds covalently to alpha1**
- can bind other receptors*
- inhibits presynaptic reuptake of NE, blocks histamine/ACh/serotonin receptors*
- long half life (24hr) –> can be used rest of life
indications: pheochromocytoma (cortisol secreting tumor)***, HTN, sweating, tachycardia
risk of shock, syncope, postural hypotension
propranolol, atenolol, labetalol
- beta blockers –> decrease HR, contractility, CO
- side effects: fatigue, bronchoconstriction, sexual dysfunction, arrhythmias (with sudden withdrawal)**
propranolol
- blocks beta1 and beta2 receptors*
- prevents arrhythmias
indications: HTN (can be combined with thiazide), angina pectoris, cardiac arrhythmias, preventing SCD and reinfarction after MI, treat heart failure, adjunct therapy with alpha blockers to treat pheochromocytoma*
contraindications: cardiogenic shock, sinus bradycardia, >1st degree heart block, bronchial asthma
also risk of hand parasthesia, depression, insomnia
atenolol
- selective beta1 receptor blocker**
indications: HTN, manage patients with suspected acute MI*, angina
contraindications: same as propranolol (except bronchial spasm) + cardiac failure
also risk of respiratory drive disorder
labetalol
- selectively blocks alpha1 and nonselectively blocks beta1 and beta2***
- fall in BP WITHOUT reflex tachycardia or reduction in HR***
indications: HTN
- 2nd go to drug in pregnancy behind methyldopa*
contraindications: same as propanolol
also risk of postural hypotension
Ca2+ channel blockers
- preferred drugs (diuretics 1st) for treating HTN*
- can use in combination
dihydropyridine –> Nifedipine, Amlodipine
-more vascular than heart effects
smooth muscle relaxation (vasodilation)
dihydropyridines
- most commonly used Ca2+ channel blocker and long lasting
- 24hr. efficacy*
- bind to L type Ca2+ channel
- high 1st pass metabolism (low bioavailability)
indications: HTN, elderly, african americans, those with low renin levels*
drug interactions: inhibit P-glycoprotein, inhibit CYP3A4 (watch for toxicity of other drugs)
risks of peripheral edema (ankle edema), hypotension, flushing**, reflex tachycardia
