HTN Flashcards
Clinical practice guidelines for normal BP? What is normal BP?
<120/80
- Promote optimal lifestyle habits
- reassess in 1 yr
Clinical practice guidelins for elevated BP? What is elevated BP?
120-129/ <80
- Non-pharmacologicla therapy
- Reassess in 3-6 mo
Clinical practice guidliens for Stage 1 HTN? What classifies as stage 1 HTN?
bp 130-139/ 80-89
- Is patient clniical ASCVD or estimated 10 y CVD risk >10%
- yes
- non pharmacological therapy and BP lowerin g meds
- reassess in 1 mo
- BP goal met?
- yes- reassess in 3-6 min
- no- assess and optimize adherence to therapy and consider intensification of therapy
- BP goal met?
- No
- non pharmacologicla therap
- reassess in 3-6 mo
- yes
What classifies as Stage 2 HTN? Clinical Practice Guidelines?
>140/90
- non pharmacologicla therapy and BP lowering meds
- reassess in 1 mo
- Bp goal met?
- yes- reasses in 3-6 mo
- no- assess and optimize adherence to therapy. consider intensification of therapy
What physiologically influences BP?
What are the various sites of action for anti-HTN?
- Brainstem- alpha 2 receptors
- clonidine
- methyldopa
- sympathetic ganglia- not as popular because influence both SNS and PSNS
- mecamylamine
- trimethapran
- Adrenergic terminals- would deplete ALL adrenergic terminals, of vesicales with NT; can cause unwanted s/e such as depression
- guanethidine
- reserpine
- Cardiac B1 receptors
- Propranolol
- metoprolol
- other B blocker
- Vascular alpha 1 receptors
- Prazosin
- Terazosin
- Labetalol
- Vascular smooth muscle
- hydralazine
- minoxidil
- nitroprusside
- diazoxide
- CCB
- Thiazides
- Renal Tubules- Decrease amt Na/H2O reabsorption
- thiazide diuretics
- furosemide
- K sparing diuretics
- Components of the RAAS- huge component is decreasing tone RAAS
- 8A- receptors on juxtaglomerular cells- propranolol, metoprolol
- 8B- Renin- aliskiren
- 8C- ACE- Captopril, enalapril
- 8D- ANGII Receptor- losartan, valsartan
- 8E - Aldosterone receptors- eplerenone, spironolactone
RAAS system and role in BP modulation?
- Renin+ angiotensinogen–> ANG I–> (via ACE)–> ANG II–> SNS activity, tubular NaCl reabsorption and K excretion, adrenal cortex to make aldosterone, arterialar vasoconstriction, ADH secretion
- Renin works to maintain tissue perfusion through increase ECF volume and increase BP
- Renin is secreted by the Juxtaglomerular Apparatus
- renin is the rate-limiting step
- released when less NaCl delivery to juxtaglomerular apparatus or when renal baroreceptors sense decreased flow
- beta 1 receptors on renal tubules also stimulated by circulating NE/Epi
- release renin when dry and BP too low
- Results in 1) vasoconstriction & 2) Na+ retention
- Renin-angiotensin system is synergistic with SNS by increasing the release of noradrenaline from the sympathetic nerve terminals
Role of ACE inhibitors to treat HTN?
- First line therapy
- HTN
- CHF
- Post-MI to reduce CHF progression
- Mitral Regurgitation
- Delay progression of renal disease
- More effective in diabetic patients- ACE inhibitors in DM can delay renal dysfunction
MOA ACE inhibitors?
- Mechanism of Action: Block the conversion of angiotensin I to angiotensin II in the vascular endothelium
- Via an interaction with the zinc ion of angiotensin converting enzyme (peptidyl-dipeptidase)
- Fall in arterial pressure
- Reduced cardiac work load
-
Get less ANGII and subsequent fall in BP
- vasodilation
- decrease blood volum
- decrease cardiac and vascular remodeling
- potassium retention
- fetal injury
-
ACE inhibitors also block bradykinin
- get vasodilation, cough and rare angioedema
What is effect on ANG II on BP? What receptor does ANG II bind to?
- Angiotensin II is a potent vasoconstrictor responsible for arterial smooth muscle constriction
- Angiotensin II
-
Main action mediated via AT-1 G-protein coupled receptor.
- Signaling results in increased Ca2+ release from the SR
-
Main action mediated via AT-1 G-protein coupled receptor.
-
AT-1 receptor effects
- Generalized vasoconstriction (especially in the afferent arterioles of renal glomeruli)
- Increased norepinephrine release
- Proximal tubular reabsorption of Na+
- Secretion of aldosterone from adrenal cortex
Examples of ace inhibitors?
- Highly Potent with minimal side effects
- Good patient compliance (end in -pril)
- Captopril- [Capoten]
- Enalapril- [Vasotec]
- Ramipril- [Altace]
- Benazepril- [Lotensin]
- Lisinopril- [Zestril, Prinivil]
- Moexipril- [Univasc]
- Quinapril- [Accupril]
- Fosinopril- [Monopril]
- Trandorapril- [Mavik]
S/E of ace inhibitors? Drug interaction? contraindications
- S/E
- prolonged hypotension intra op (prohibit taking on AM of sx)
- granulocytopenia
- angioedema d/t bradykinin
- persistent cough d/t bradykinin
- hyperkalemia (esp CRI)
- Drug interaction: NSAIDs antagonize its effects, other anti-HTN additive effect
- NSAIDs inhibit prostaglandin, which is a vasodilator. Giving NSAIDS stop vasodilation, kind of working against ACE vasodilation.
- Contraindication
- pregnancy
- renal artery stenosis patients may develop renal failure due to impaire efferent arteriole constriction
- renal artery stenosis patients rely on efferent vasoconstriction to maintain GFR
ACE inhibitor pharmacologic effects?
- all affect venous and arterila system evenly
- enalapril and ramipril are prodrugs
- peak times can be 4-8 hours after dose, with duration lasting 18-30 hours (enalapril) or 24-60 hours (ramipril)
MOA Angiotensin II Receptor Blockers? S/E? Contraindications?
- Angiotensin II (AT1) receptor antagonists
- MOA: Competitive binding to inhibit the action of angiotensin II at its receptor
- Blocks the vasoconstrictive actions of angiotensin II without effecting ACE activity
- results in decreased peripheral vasoconstriction
- Side effects similar to ACE inhibitors
- No significant bradykinin accumulation (avoid cough side effect)
- Contraindication:
- renal artery stenosis
- pregnancy
Examples ARBS?
- Losartan-[Hyzaar, Cozaar]
- Valsartan- [Diovan]
- Irbesartan- [Avalide, Avapro]
- Candesartan- [Atacand]
- Telmisartan- [Micardis]
- Eprosartan- [Teveten]
- Olmesartan- [Benicar]
- Tasosartan- [Verdia]
MOA hydralazine? Dose?
- direct arterial vasodilator, second- line
- reserved for cases not responding and in pregnancy
- used in OR frequently when beta blockers are contraindicated
- Vasodilation through activation of guanylate cyclase (interferes with action of IP3 mediated calcium release from SR) and hyperpolarization
- Produces direct relaxant effect on vascular smooth muscle and decrease in SVR
- arteries > veins
- Alter Ca2+ transport in vascular smooth muscles
-
Dosage 2.5-10mg IV
-
10-20minutes peak, can last up to 6hrs
- be careful/patient when titrating hydralazine
-
10-20minutes peak, can last up to 6hrs
Pharmacokinetic hydralazine?
- Extensive hepatic first pass metabolism
- Onset 15 minutes give slowly
- Elimination ½ time 3 hours
- After IV < 15% appears unchanged in the kidney
S/E Hydralazine?
- Angina with EKG changes
- DBP reduced >SBP- potential impairment coronary perfusion
- Reflex Increase HR, SV, CO
- Tolerance & Tachyphylaxis
- Sodium and H20 retention- from compensatory action of aldosteron from drop in BP. May need to give BB and diuretic with hydralazine
- Systemic lupus like syndrome
Clinically used in combination with BB and diuretic
- Limits the increased SNS activity
- Also, used in CHF (combined with isosorbide mononitrate)
- speicfically helpful in black patients not traiditonally responding to BP meds
Minoxidil MOA and use?
Mechanism of Action
- KATP channel opener: resulting in hyperpolarization (decreased voltage-gated Ca2+ channel activity) and vasodilation
- Directly relaxes the arteriolar smooth muscle little effect on venous capacitance
- Orally active
- Very potent; activity via active sulfate metabolite
Clinically used (2nd line drug with severe forms HTN)–refractory HTN, if patient on this drug, do thorough cardiac w/u)
- To treat the most severe forms of hypertension due to
- renovascular disease
- renal failure
- transplant rejection
- used in combination with beta-blocker (offset reflex tachycardia and compensatory aldosterone activation) & diuretic (to offset sodium and water retention)
- Topical formulation used to treat baldness (side effect hirsutism)
Pharmacokinetics minoxidil?
- Pharmacokinetics
- 90% oral dose absorbed from the GI tract
- Peak levels in 1 hour
- E ½ t 4 hours
- 10% of drug is recovered unchanged in the urine