HTN II

Question 1

Primary agents

Answer 1

• diuretics (thiazide-type)
• ACE inhibitor
• angiotensin II receptor antagonists
• calcium channel blockers

Question 2

Secondary agents

Answer 2

• diuretics (loop, potassium sparing, and aldosterone antagonists),
• renin inhibitor,
• sympatholytic agents (β receptor antagonists, α1 receptor antagonists, central α2-agonists)
• direct vasodilators

Question 3

Clonidine (Catapres)

Answer 3

• MOA : a2-agonist –> reduces release of NE –> inhibit SNS
• Sympatholytic agents
• Stimulate I1 receptors –> AntiHTN
• Can also treat ADHD
• PK : lipid soluble and rapidky enters the brain
• SE : Dry mouth, sedation, rebound effect
• DDI with TCA’s

Question 4

Methyldopa

Answer 4

• Sympatholytic agent
• Inhibits DOPA Decarbolase –> reduce Dopamin and NE
• HTN during pregnancy or gestational HTN
• Enters brain via Aromatic AA transporter
• Also cause rebound efftect

Question 5

Atenolol (Tenormin) and Metoprolol (Lopressor)

Answer 5

• Selective β1 blockade
• advantageous in treating hypertensive patients who also suffer from asthma, diabetes, or peripheral vascular disease.

Question 6

Carvedilol (Coreg), Labetalol (Trandate), and Nebivolol (Bystolic)

Answer 6

• β –blockade and vasodilation
• Carvedilol and labetalol are racemic mixtures that contribute to block both α and β receptors.
• Nebivolol:
  
  • selectively blocks β1 receptors without α blockade.
  • releases NO from endothelial cells and causes vasodilation.
• Carvedilol reduces mortality in patients with heart failure and is particularly useful in patients with both heart failure and hypertension.
• Labetalol: hypertensive emergencies or hypertension associated with pheochromocytoma.

Question 7

Acebutolol (Sectral), Penbutolol (Levatol), and Pindolol (Visken)

Answer 7

• β –blockade and ISA
• partial agonists.
• They antagonize β receptors with some intrinsic sympathomimetic activity (ISA).
• beneficial for patients with bradyarrhythmias or peripheral vascular disease.

Question 8

Esmolol (Brevibloc)

Answer 8

• β1 with shortest half-life (i.v.)
• Due to the hydrolysis of ester linkage, esmolol has the shortest half-life (9 to 10 min).
• used for management of intraoperative and postoperative hypertension as well as hypertensive emergencies.

Question 9

Prazosin (Minipress), Doxazosin (Cardura), and Terazosin (Hytrin)

Answer 9

• Selective α1 blockade
• Alpha-Adrenoceptor-Blocking Agents
• Blocks α1 receptors in arterioles and venules⇒ dilution of both resistance and capacitance vessels.
• less reflex tachycardia when lowering blood pressure than do nonselective α antagonists
• Indicated for men with concurrent hypertension and benign prostatic hyperplasia.
• SE : orthostatis hypotension; Palpitation, headache, and dizziness.

Question 10

Phentolamine (Regitine) & Phenoxybenzamine (Dibenzyline)

Answer 10

• Alpha-Adrenoceptor-Blocking Agents
• Non-selective α blockade
• hypertension associated with pheochromocytoma or clonidine withdraw syndrome when combing with β-blockers

Question 11

Nifedipine (Adalat) or other DHPs

Answer 11

• Vasodilation, thus reduce arteriolar resistance by blocking L-type Ca2+ channels.
• Sustained-release form for the treatment of hypertension, angina pectoris, Raynaud’s disease, and premature labor.
• Grapefruit and other CYP3A4 inhibitors may enhance the levels of nifedipine.
• Adverse Effects: Constipation, dizzy, tachycardia, dose-related pedal edema, etc

Question 12

Verapamil (Calan, Verelan) and Diltiazem (Cardizem)

Answer 12

• Verapamil and diltiazem are relatively selective for the myocardium calcium channels although they have both cardiac depressant and vasodilation.
• Hypertension, angina pectoris, arrhythmia
• Constipation (7.3%), dizzy, nausea, hypotension, bradycardia
• avoid routine use with beta blockers due to increased risk of bradycardia and heart block

Question 13

Direct Vasodilators–ATP-dependent Potassium Channel Openers

Answer 13

1) . Minoxidil (Rogaine)
2) . Hydralazine (Apresoline)

Question 14

Minoxidil (Rogaine)

Answer 14

1. opening of ATP-dependent potassium channels in smooth muscle membrane.
2. Hyperpolarization due to outflow of K+ stabilizes the membrane at its resting potential
3. reduces the opening of voltage-dependent calcium channels
4. leads to arteriolar relaxation but not veins.
   
   • Hypertension, androgenic alopecia ( Hair Loss)

Question 15

Hydralazine (Apresoline)

Answer 15

 Opening of K+ channels

 Inhibiting IP3-induced Ca2+ release from Sarcoplasmic reticulum

 Release of NO from endothelium

• Severe hypertension. Certain patients have tolerance and tachyphylaxis to hydralazine.
• Reflex sympathetic activation, headache, nausea, etc. Lupus erythematosus.

Question 16

Vasodilators

Answer 16

• Potent vasodilation and activated baroreceptor reflex : DHP > diltiazem > verapamil.

Question 17

Cardiac depressants

Answer 17

• Potent inhibition of cardiac contractility and conduction : Verapamil > diltiazem > DHP.