Falcon 2012: Blood Pressure medication

Question 1

List agents acting on CNS

Answer 1

alpha-Methyldopa, Clonidine, Reserpine

Question 2

alpha-Methyldopa

Answer 2

• Pro-drug: converted to alpha-methyl-NE (more selective for alpha-2 receptors)
• DOC for mild to moderate HTN in preggos
• Classic SE: Coombs positive hemolytic anemia

Question 3

Clonidine

Answer 3

Activates pre-synaptic alpha-2 –> decreases NE release –> decreased CO and vascular tone
- NOT 1st line medication (associated with severe rebound syndrome if abruptly stopped)

Question 4

Reserpine

Answer 4

Destroys NE storage granules in peripheral and central nerve terminals

• Can cause depression-like syndrome
• Safe and effective if used in small doses

Question 5

List agents that work on PNS

Answer 5

Guanethidine, “-zosins”, beta-blockers

Question 6

Guanethidine

Answer 6

• “false” neurotransmitter
• concentrates into vesicles and displaces NE, but is inactive at adrenergic receptors
• Major SE: Orthostatic HypoTN and retrograde ejaculation

Question 7

Prazosin, Doxazosin, Terazosin

Answer 7

alpha-1 antagonist –> decreased arteriolar resistance
SE: “1st dose” syncope and orthostatic HypoTN (very strong antihypertensive)
- Favorable effect on plasma lipids (decreases LDL, increases HDL)
- Also used for BPH to prevent urinary retention

Question 8

Beta-blockers

Answer 8

• Decreases HR and ionotropy –> decrease CO
• Abrupt withdrawal may result in rebound HTN
• SE: different for different beta-blockers
  NOTE: When switching from one beta-blocker to another: wait 2-3 half lives (possible to induce AV or SA nodal blockade, especially in patients with coronary disease)

Question 9

Non-selective beta-blockers

Answer 9

Propranolol, Nadolol, Timolol
Propranolol - effective for anxiety/panic disorders
*Propranolol and Nadolol are used more for portal HTN in patients with cirrhosis
Timolol - very lipophilic –> high CNS penetration; used as eyedrops for glaucoma

Question 10

Non-selective beta and alpha blockers

Answer 10

Labetalol (also partial agonist for beta-2), Carvedilol

• Labetalol - used for acute BP control and cocaine overdose (alpha blockade by these drugs prevent vaso-occlusion induced by cocaine which can occur with other beta-blockers)
• Carvedilol - also given for CHF

Question 11

Beta partial agonists

Answer 11

Pindolol - beta non-selective

Acebutolol - beta-1 selective

Question 12

Beta-1 selective blockers

Answer 12

Esmolol - 4 min half life –> IV infusion
Metoprolol - most commonly prescribed beta blocker for HTN
Atenolol - older, but still used

Question 13

List vasodilators

Answer 13

Hydralazine, Nitroprusside

Question 14

Hydralazine

Answer 14

Dilates peripheral arteries –> short term Rx for moderate to sever HTN
- Safe for preggos in HTN emergency
SE: HA, flushing, sweating (due to low BP and vessel dilation), SLE-like syndrome (more common in “slow acetylators”)

Question 15

Nitroprusside

Answer 15

-IV infusion for HTN emergencies
- Metabolized to NO –> increases cGMP –> smooth muscle relaxation
AE: HypoTN, converted to cyanide (give sodium thiosulfate with extended infusions to detoxify cyanide)

Question 16

Calcium channel blockers

Answer 16

Nifedipine and Diltiazem (elective for peripheral vessels), Verapamil (heart selective)
- Vasodilate arterioles and coronary vessels, decrease cardiac contractility and AV nodal conduction
- Very useful in HTN due to low renin that is NOT related to low renal perfusion
- Used in angina to decrease CO
CI: WPW (may encourage aberrant pathway)

Question 17

ACE inhibitors

Answer 17

"-prils" (Captopril, Lisinopril, etc.)
Long term benefits in patients with:
- post-MI ventricular dysfunction
- Diabetic nephropathy 
- Heart failure 
MOA: blocks conversion of AT I to AT II --> decreased aldosterone and vasoconstrictive effects of AT II; inhibits bradykinin breakdown

Question 18

ACE inhibitors and bradykinin

Answer 18

ACE inhibitors prevents bradykinin breakdown:

• persistent dry cough
• life-threatening angioedema (rare): usually ~1 week after start of medication (treatment is similar to anaphylactic rxn, may need to be intubated)

Question 19

ARBs (AT II receptor blockers)

Answer 19

Candesartan, Losartan, Valsartan

• Similar to ACE inhibitors but without affect on bradykinin
• Very well tolerated by patients (“better than placebo”)

Question 20

SE for ACE inhibitors and ARBs

Answer 20

HypoTN, hypovolemia, hyperkalemia, taste changes (especially with Captopril)
*Captopril is a sulfa drug

Question 21

CI for ACE inhibitors and ARBs

Answer 21

1. B/L renal artery stenosis (AT II constricts efferent arterioles and can maintain adequate GFR when renal perfusion pressure is low)
2. Preggos: inhibit fetal renal function –> fetal HypoTN–> decreased urine output –> oligohydramnios