Exam 1: Lecture 6: Antihypertensive drugs II Flashcards
Benefits of lower sodium diet on hypertension?
moderate reduction in dietary sodium can reduce BP by 4.8/2.5 in hypertensive individuals, 1.9/1.1 in normotensive people
Benefits of weight loss on hypertension?
can lead to reduction in BP by 0.5-2/kg Diastolic
DASH
The Dietary Approaches to Stop Hypertension
DASH Diet
High in veggies, fruit, low-fat dairy, whole grains, poultry, fish and nuts
low in sweets, sugar, red meats….saturated fat, total fat and cholesterol
Benefits of exercise on hypertension?
can decrease systolic by ~4/6, and diastolic by ~3.
have to be consistent, 3-4 sessions per week with moderate intensity
What detects BP?
Baroreceptors
arterial baroreceptors become less sensitive in primary hypertension
Where does CO and PVR regulation occur?
- Resistance Arterioles
- Capacitance Venules
- Pump output heart
Baroreflex and baroreceptor steps
- Mechanical forces (shear stress.compression,) in arteries
- Change in tension detected by Piezo channels (working on drugs that act at PIEZO1 channel)
- Cation influx
- Transmission of action potential and activation of down stream signaling
negative feedback loop
Polypharmacy
using multiple medications
Example: Hydralazine has to have a B-blocker and diuretic added
Renin is secreted in response to…
decreased renal artery blood volume
Sympathetic activation
Angiotensin II causes….
constriction of vessels = increasing PVR
Secretion of aldosterone, promoting increase Na reabsorption and blood pressure
Secretion of AVP, increasing blood volume
Angiotensin II….
Acts at multiple AT receptors but causes vasoconstriction at AT1Rs
Gaq coupled (Gaq -> increase PLC -> PIP2 convert to IP3 and DAG -> increase Ca release -> activation of MLCK -> phosphorylation of MLC -> contraction of SM
Captopril (capoten)
Sulfhydryl-containing ACEi
** only one to cross BBB **
some evidence for mood elevation
Indicated: hypertension and heart failure
Rapid onset
Adverse effects: Postural Hypotension, edema, cough, itching, headache, chest pain, metallic taste (-SH group)
Enalapril (Vasotec)
First in class dicarboxylate ACEi
Preg class D, cannot be used
Pro drug, active metabolite is enalaprilate
Indicated: hypertension, heart failure, left ventricle dysfunction
developed to remove -SH (metallic taste)
Adverse effects: Dizziness, hypotension, syncope, cough, edema
Lisinopril
2nd gen dicarboxylate ACEi
peptide derivative of captoril, not a pro drug
Indicated: hypertension, heart failure, used after acute MI and for diabetic nephropathy
Adverse effect: Dizziness,hypotension,syncope,cough,edema (often given with diuretic)
Losartan
ARBs, used in patients that don’t tolerate ACEi well
** Most common formulation is a tetrazole-potassium salt
Indicated: hypertension, heart failure, diabetic nephropathy
Adverse effects: dizziness, headache, studies of increased risk of MI and cancer
Aliskiren
Renin inhibitor
Developed for primary hypertension
clinical trials halted a bunch
cant be used with ACEi, ARBs, patients with renal impairment
contraindicated in pregnancy and not a 1st choice med
Sodium nitroprusside
Nitrix oxide donor
indicated: infusion for hypertensive crisis or acute heart failure
interacts with oxyhemoglobin in arterioles and venues to release NO, causing dilation of arterioles/venules and therefore decrease afterload and venous preload
bunch of adverse effects: cyanide toxicity, methemoglobinemia, Brady- or tachy- arrhythmia, hypotension, headache, dizziness, palpitations,
Hydralazine
Direct-smooth muscle relaxants
Indications: Hypertensive crisis, acute emergent secondary hypertension, rarely as maintenance
used in surgery,ICU, pregnancy
inhibits the release of Ca from Sr in response to increase IP3, decreasing PVR and Afterload
removes 2nd wave but not 1st of contractility
Guanethidine
reduces release of catecholamines
Does not cross BBB, no longer used in USA
toxicities include: progressive loss of sympathetic nerve terminals.
side effects: hypotension, sexual dysfunction and diarrhea
numerous adverse drug interactions including with OTC pseudoephedrine
