Flashcards in Pharmacology: Katzung Drugs used in Hypertension Deck (73):
What diuretics are used to treat hypertension?
What is the MOA and clinical applications for hyrochlorothiazide and chlorothalidone?
They block the Na/Cl transporter in the distal convoluted tubule and are used for
(2) mild edema
What is the MOA and clinical application for Furosemide?
Furosemide blocks the Na/K/2Cl transporter in the TALH. It is used for
(2) Heart failure
What adverse effects are associated with Hydrochlorothiazide and chlorothalidone?
(2) metabolic alkalosis
What are the adverse effects associated with Furosemide?
Why are diuretics used to treat hypertension?
Because diuretics will decrease blood volume and this will decrease the systemic blood pressure.
What are sympathoplegics?
Sympathoplegics are durgs that interfere with sympathetic control of cardiovascular function
Why are sypathoplegics used to treat hypertension?
Because they can decrease venous tone, HR, contractile force, cardiac output, and total peripheral resistance. Altogether this will decrease the blood pressure.
What centrally acting sympathoplegics are used to treat hypertension?
What is the MOA of clonidine?
clonidine is an alpha 2 agonist that decreases sympathetic outflow
What are the adverse effects associated with clonidine?
(2) Danger of rebound hypertension if drug is stopped.
(3) dry mouth
What is the MOA for methyldopa?
Methyldopa is a prodrug that is converted to methylnorepinephrine in the CNS with results like clonidine.
What are the adverse effects associated with methyldopa?
(2) hemolytic antibodies (positive coombs test)
What are the ganglion blocking drugs that can be used to treat hypertension?
(1) Hexamthonium (obsolete)
What is trimethaphan used for?
Trimethaphan is used as a short acting ganglion blocker in hypertensive emergencies. Creates controlled hypotension.
What is mecamylamine and what is it used for?
Mecamylamine is an oral ganglion blocker with a duration of several hours which is under investigation for use in smoking cessation.
What is the major compensatory response to ganglion blockers?
What toxicities are associated with ganglion blockers?
(1) blurred vision
(3) urinary hesitancy
(4) sexual dysfunction (sympathetic blockade)
(5) orthostatic hypotension (sympathetic blockade
Which post ganglionic neuron blockers are used to treat hypertension?
What are the clinical applications and MOA of reserpine?
reserpine blocks the loading of vesicles with catecholamines. It is used to treat
(2) Huntington's disease
What are the adverse effects associated with reserpine?
(2) severe psychiatric depression (at high doses)
What are the adverse effects and MOA of Guanethidine?
Guanethidine blocks re-uptake of norepinephrine. However, it causes severe orthostatic hypertension and is therefore no longer used.
Why are post ganglionic blockers used to treat hypertension?
Because they deplete stores of catcholamines thus inhibiting sympathetic activity. This decreases cardiac output and TPR.
What is the compensatory response to post ganglion blockers?
salt and water retention
Which alpha blockers are used to treat hypertension?
What is the mechanism of action for alpha blockers?
The alpha blockers
(1) reduce TPR
(2) reduce prostatic smooth muscle tone
What is prazosin used for?
(1) mild hypertension
(2) benign prostatic hyperplasia.
What adverse effects are associated with prazosin?
First dose orthostatic hypertension.
What differentiates doxazosin and terazosin from prazosin?
doxazosin and terazosin have a longer duration of action.
Which beta blockers are used to treat hypertension?
What is the mechanism of action for propranolol?
Propranolol is a non selective beta blocker that reduces cardiac output and possibly renin release also.
What are the adverse effects associated with the beta blockers?
(1) bronchospasm in asthmatics
(2) excessive cardiac depression
(3) sexual dysfunction
(5) sleep disturbances
What differentiates Atenolol and metoprolol from propranolol?
Atenolol and metoprolol are beta 1 selective and have fewer adverse effects.
What differentiates Labetalol and carvedilol from propranolol?
Labetalol and carvedilol are alpha and beta blockers and can be given orally and parenterally.
What calcium channel blockers are used to treat hypertension?
Why are calcium channel blockers used to treat hypertension?
they relax vascular smooth muscle and reduce cardiac output. They can also be given orally.
What is the mechanism of action for the calcium channel blockers?
They inhibit L-type calcium channels thus reducing contractility in smooth/cardiac muscle.
What are the clinical applications for Verpamil and Diltiazem?
verpamil and diltiazem and used for
What are the adverse effects associated with calcium channel blockers?
(1) Excessive cardiac depression
What differentiates nifedipine and the dihydropyridines from verpamil and diltiazem?
Nifedipine and the dihydropyridines are more vasodilatory and less cardiosupressant.
What are the older oral vasodilators?
What is the MOA of hydralazine?
it causes the release of NO by endothelial cells causing arteriolar dilation
What are the clinical applications of Hydralazine?
(2) heart failure
What are the adverse effects associated with hydralazine?
(2) salt/water retention
(3) lupus like syndrome
What is the MOA for Minoxidil?
Minoxidil is a prodrug sulfate metabolite that opens K+ channels and causes arteriolar smooth muscle hyperpolarization and vasodilation
What are the clinical applications for minoxidlil?
(1) severe hypertension
(2) male pattern baldness
What adverse effects are associated with minoxidil?
(1) marked tachycardia
(2) salt and water retention
Which parenteral vasodilators are used to treat hypertension?
What is the MOA of Nitroprusside?
It releases NO from the drug molecule
What are the clinical applications for Nitroprusside?
(1) Hypertensive emergencies
(2) cardiac decompensation
What are the adverse effects associated with Nitroprusside?
(1) excessive hypotension
(2) Prolonged infusion may cause thiocyanate or cyanide toxicity.
What is the MOA for Diazoxide?
Diazoxide opens K+ channels in smooth muscle and secretory cells.
What are the clinical applications for Diazoxide?
(1) hypertensive emergencies
(2) Hypoglycemia due to insulin secreting tumors.
What are the adverse effects associated with Diazoxide?
(3) Excessive hypotension.
What is the mechanism of action for fenoldopam?
Fenoldopam is a D1 agonist that causes arteriolar dilation
What are the clinical uses for fenoldopam?
What adverse effects are associated with Fenoldopam?
Which drug functions as a Renin antagonist?
What is the MOA of Aliskiren?
It is a renin inhibitor that reduces angiotensin I synthesis.
What is the clinical application for aliskiren?
It is used for hypertension
What adverse effects are associated with aliskiren?
(2) Renal impairment
To what class of drugs do Captopril, benzapril, enalapril, and lisinopril belong to?
They are all ACE inhibitors
What is the MOA of ACE inhibitors?
ACE inhibitors prevent the conversion of angiotensin I to angiotensin II by angiotensin converting enzyme.
What are the clinical applications for ACE inhibitors?
(2) diabetic renal failure
(3) heart failure
What are the adverse effects associated with ACE inhibitors?
Hyperkalemia, teratogen, cough
contraindicated in Pregnancy
Lower angiogensin II and aldosterone
What differentiates Captopril from the other ACE inhibitors?
Captopril has a shorter half life.
To what class of drugs do Losartan, Candesartan, and irbesartan belong to?
They are angiotensin II receptor blockers (ARBs)
What is the MOA of ARBs?
They block angiotensin receptors thus preventing angiotensin mediated vasoconstriction and fluid retention.
What are the clinical uses for ARBs?
They are used for hypertension.
What are the adverse effects associated with ARBs?
What are the five components to the stepped care of hypertension?
Used in more severe hypertension
(1) lifestyle changes
(3) sympathoplegics (beta blockers)
(4) ACE inhibitors
(5) Vasodilators (calcium channel blockers)
What drugs are more likely to be effective in treating hypertension in older patients?
Older patients respond better to diuretics and beta blockers than to ACE inhibitors