Hypertension - Lecture 2 (CCB Drugs) Flashcards
CCB MOA
Vasodilator activity by inhibiting Ca influx across slow channels of vascular smooth muscle and myocardium during depolarization, relaxing coronary vascular smooth muscle and coronary vasodilation
Non-Dihydropyridine CCB MOA
Decrease contractility -> decrease SV -> decrease CO
**Cardiac smooth muscle CC
Dihydropyridine CCB
dilate peripheral arterioles -> Decrease PVR
**periphery smooth muscle channels
Dihydropyridine CCB MOA
act on vascular smooth muscle, dilate peripheral arteries (decrease PVR)
Most used
Amlodipine (Norvasc) Dose and Frequency
5-10mg, Daily
Nifedipine long acting (Adalat CC, Nifedical XL, Procardia XL) Dose and Frequency
60-120mg, Daily
Non-Dihydropyridine CCB MOA
Decrease HR and conduction across AV node
Negative inotropic and chronotropic effects
decrease contractility -> decrease SV -> decrease CO
Diltiazem (Cardizem CD/LA/DR, Cartia XT, Dilacor XR, Taztia, Tiazac) Dose and Frequency
120-540mg, Daily
Non-D
Verapamil long acting (Calan SR)
120-480mg, Daily…sometimes BID
Non-D
Verapamil (Calan PM)
100-400, Daily in PM
Non-D
Dihydropyridine Clinical Considerations
1st line therapy w/o compelling indication
Preferred in black people
Effective older people w/ Isolated Systolic Hypertension
Indicated in stable CAD
Non-Dihydropyridine Clinical Considerations
indicated for cardiac focused benefit
Angina
Atrial fibrillation/flutter
PSVT
*Verapamil = migraine prophylaxis
ADE of non-Dihydropyridine
Bradycardia
Constipation w/Verapamil
ADE of Dihydropyridine
Reflex tachycardia
Pedal Edema
ADE common to both CCB
Gingival Hyperplasia
Headache
Orthostatic Hypotension
Dizziness
What to monitor with CCB?
BP
HR
Orthostatic
Edema
Non-DHP contraindications?
Heart Block
HF (Amlodipine/felodipine OK)
Avoid B-blockers
Drug interactions CCB
Simvastatin Dosing limitations
no more than 20mg w/ Amlodipine
no more than 10mg w/ Verapamil/Diltiazem
Alcohol effects on CCB?
increased effects
Direct Vasodilator MOA
Act directly on vascular smooth muscle to dilate arterioles
can have reflex tachycardia
Hydralazine (Apresoline) Dose and Frequency
20-200mg, 2-4/day
Clinical Considerations Direct Vasodilators
4th line
Likely add-on resistant HTN
What to monitor with Direct Vasodilators?
BP HR SCr Hypotension Edema
Topical Minoxidil indicated in….
alopecia due to side effect
ADE of Direct Vasodilators
Reflex Tachycardia, palpitations Headache/dizziness Na/H2O retention Hirsutism Lupus-like Syndrome
Where do Thiazide diuretics work?
DCT
Inhibit NaCl reabsorption
Where do K+ Sparing Diuretics work?
Collecting Duct
limit Na+ reabsorption/K+ secretion
Where do Loop Diuretics work?
Ascending Limb
inhibit NaCL reabsorption
Thiazide Diuretics MOA
increase NA and H2O excretion
Decrease Vol -> Decrease preload -> decrease SV -> decrease CO
HCTZ Dose and Frequency
12.5-25mg, Daily
Chlorthalidone Dose and Frequency
12.5-50mg, Daily
Which thiazide is better?
Chlorthalidone (more potent), w/ better outcomes but we use HCTZ more
But HCTZ comes in come combos
Which allergy should you not use HCTZ with?
Sulfonamides (Bactrim)
When switching between HCTZ and Chlorthalidone, what’s equivalent?
12.5mg Chlorthalidone = 50mg HCTZ
thiazide Clinical Considerations
if CrCl <30ml/min = not useful
Dose over 50mg/day chlorthalidone = potential hypokalemia
dose >25mg/day HCTZ = increased ADE
Loop Diuretics MOA
increase NA and H2O excretion
Decrease Vol -> Decrease preload -> decrease SV -> decrease CO
More potent than thiazides
furosemide (Lasix) Dose and Frequency
20-80mg, 1-2/day
Loop Diuretics Uses…
used more in patients who have fluid accumulation
Dosing equivalents Loops
Bumetenide 1mg
Torsemide 20mg
Furosemide 40mg
All equal
Clinical Considerations Loops
Can result in hypokalemia, give w/ K+ supplement if needed
Work at CrCl < 30ml/min
** Sulfa allergy should avoid if serious allergy**
K+ sparring diuretics Clinical Considerations
not recommended for initial treatment of HTN
Weak diuretics
Avoid in patients with significant CKD
Contraindicated if K >5.5, receiving K+ supp, or meds that increase K+
People with gout should be cautious of which diuretics?
Thiazide and loops cause they can increase uric acid levels
Drug interactions Diuretics?
NSAIDs (can cause water retention)
ACEi/ARBs (K+ Sparring only)
high salt food = less efficacy
What to monitor when on Diuretics?
Cr Bun Electrolytes (Na,K,Etc) Uric Acid Blood Glucose
Diuretic side effects?
Dehydration
Hypotension w/ position change
Stimulation of a1 results in…
Vasoconstriction
Bladder sphincter contraction
Reduced lipolysis
Stimulation of a2 results in…
Decrease pre-synaptic NE release (Reduced sympathetic outflow)
Example of DHP CCB
Amlodipine
Nifedipine
Example of Non-DHP CCB
Verapamil
Diltiazem
Verapamil and Diltiazem are substrates of which CYP?
P450
What to monitor with vasodilators?
BP HR Hypotension Edema Scr
