Anti-Hypertensive Drugs I Flashcards
Name the major classes of diuretics used to treat HTN.
- Thiazides (Hydrochlorothiazide, chlorthalidone))
- Loop Diuretics (furosemide)
- K sparing diuretics (spironolactone)
Name the major classes of RAAS inhibitors used to treat HTN.
- ACE inhibitors (lisinopril)
- Angiotensin receptor blockers (losartan)
Name the major classes of vasodilators used to treat HTN.
- Direct acting (Nitroprusside, Hydralazine)
- Calcium entry blockers (Verapamil)
Name the major types of sympatholytics used to treat HTN.
- Act within CNS (clonidine)
- Act on autonomic ganglia (trimethaphan)
- Act on post-ganglionic neurons (reserpine)
- Block peripheral adrenergic receptors (atenolol, prazosin, labetolol)
What is Lisinopril (Prinivil™, Zestril™; also captopril, enalapril, ramipril)?
Lisinopril is a drug of the angiotensin-converting enzyme (ACE) inhibitor class (RAAS inhibitor) used primarily in treatment of hypertension, congestive heart failure, and heart attacks, and also in preventing renal and retinal complications of diabetes.
Costs $4 to $56 per month
To what drug class does Lisinopril belong?
Pharmacologic class => ACE inhibitor
Therapeutic class => antihypertensive, treatment of CHF, preserving renal function, preserving LV function after MI, acute management of MI
Describe the pharmacodynamics of Lisinopril.
- Inhibits conversion of AT I to AT II by ACE
- Diminishes both vasocontriction and stimulation of aldosterone secretion by AT II
Describe the pharmacokinetics of Lisinopril.
- Well absorbed
- Onset 1 h, peak 6 h, duration 24 h
- Taken once a day is fine
- Excreted primarily in urine as unchanged drug
What toxicity is associated with Lisinopril?
- Orthostatic hypotension
- Use with caution in patients with impaired renal function, or renal artery stenosis
- Be careful in patients on diuretics, or those with aortic stenosis
- Angioedema, cough
- Acute renal failure
What interactions should be noted with Lisinopril?
- Additive effects with most other antihypertensives
- NSAIDs may reduce ability to lower BP
- Hyperkalemia with KCl
What special considerations should be made with patients on Lisinopril?
- Often discontinue diuretics prior to beginning use to reduce hypotension
- Category C/D in pregnancy, abnormal cartilage development
Describe the indications/dose/route for Lisinopril.
- Begin 10 mg per day, titrate slowly upward to 40 mg per day max
What should be monitored in patients on Lisinopril?
BP, weight, edema, K, BUN, creatinine
What is Hydrochlorothiazide (HydroDiuril™; also chlorthalidone)?
Hydrochlorothiazide is a diuretic drug of the thiazide class that acts by inhibiting the kidneys’ ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is believed to lower peripheral vascular resistance.
It is on the World Health Organization’s List of Essential Medicines, a list of the most important medications needed in a basic health system.
Costs $4-$50 per month
To what drug class does hydrochlorothiazide belong?
Pharmacologic class => thiazide diuretic
Therapeutic class => diuretic, antihypertensive
Describe the pharmacodynamics of hydrochlorothiazide
- Block reuptake of Cl and Na from tubular fluid after glomerular filtration
- Cause decrease in SVR (unclear mechanism)
- Lowers BP by up to 10-15 mm in many patients
- Useful as monotherapy or in combinations
- HCTZ most commonly used, but chlorthalidone may be more effective
Describe the pharmacokinetics of hydrochlorothiazide
- F ~70%, excreted unchanged in urine
- Short half-life (hours)
- HCTZ not available in IV formulation
- Onset 2 h, peak 5 h, duration 10 h
What toxicity is associated with hydrochlorothiazide?
- Allergy to sulfa antibiotics
- Cause K and Mg depletion
- Cause Na and Cl depletion => metabolic alkalosis
- Volume depletion
- Worsen hyperuricemia
What interactions should be noted in patients on hydrochlorothiazide?
Additive effects with most other antihypertensives
What special considerations should be made for patients on hydrochlorothiazide?
- More side effects in geriatric patients
- Pregnancy Class D
- Much less effective in patients with reduced GFR
Describe the indications/route/dose for hydrochlorothiazide.
- 12.5 mg or 25 mg po every morning
- Little benefit (and more toxicity) when given in higher doses
What should be monitored in patients on hydrochlorothiazide?
BP, weight, edema, K, Mg, BUN, creatinine
What is losartan (CoZaar™)?
Losartan is angiotensin II receptor antagonist drug used mainly to treat high blood pressure, especially for patients under 55 who cannot tolerate an ACE inhibitor
To what drug class does losartan belong?
Pharmacologic class => angiotensin-1 receptor blocker (ARB)
Therapeutic class => antihypertensive, preserve renal function, treatment of CHF