Podcast
Questions and Answers
What is the pharmacologic action of organic nitrates?
What is the pharmacologic action of organic nitrates?
- Bronchodilation
- Vasoconstriction
- Vasodilation (correct)
- Cardiac stimulation
How can nitrate tolerance be managed to avoid its development?
How can nitrate tolerance be managed to avoid its development?
- Using nitrates on an empty stomach
- Combining nitrates with ACE inhibitors
- Taking nitrate-free intervals (correct)
- Increasing the nitrate dosage
What is a common adverse effect of potassium channel activators?
What is a common adverse effect of potassium channel activators?
- Tachycardia
- Hyperkalemia
- Hypotension (correct)
- Hypertension
What is a contraindication of PDE5 inhibitors?
What is a contraindication of PDE5 inhibitors?
How do Viagra® and Cialis® differ in terms of duration of action?
How do Viagra® and Cialis® differ in terms of duration of action?
Which type of drugs are vasodilators?
Which type of drugs are vasodilators?
What is the pharmacologic action of potassium channel activators?
What is the pharmacologic action of potassium channel activators?
How do organic nitrates primarily function?
How do organic nitrates primarily function?
What is a common adverse effect of PDE5 inhibitors?
What is a common adverse effect of PDE5 inhibitors?
How do organic nitrates differ from potassium channel activators in terms of mechanism of action?
How do organic nitrates differ from potassium channel activators in terms of mechanism of action?
What is a key difference between Viagra® and Cialis®?
What is a key difference between Viagra® and Cialis®?
Which class of drugs is known for activating potassium channels?
Which class of drugs is known for activating potassium channels?
How does nitrate tolerance affect the efficacy of nitrates?
How does nitrate tolerance affect the efficacy of nitrates?
What is a common adverse effect associated with PDE5 inhibitors?
What is a common adverse effect associated with PDE5 inhibitors?
How do ISDN and ISMN differ in terms of their pharmacologic action?
How do ISDN and ISMN differ in terms of their pharmacologic action?
What is a key difference between the mechanism of action of organic nitrates and potassium channel activators?
What is a key difference between the mechanism of action of organic nitrates and potassium channel activators?
Which drug class is known for its ability to prevent the breakdown of cGMP in smooth muscle cells?
Which drug class is known for its ability to prevent the breakdown of cGMP in smooth muscle cells?
What is a common adverse effect associated with nitrate therapy?
What is a common adverse effect associated with nitrate therapy?
How do ISDN and ISMN differ in terms of their administration route?
How do ISDN and ISMN differ in terms of their administration route?
What is a major difference between Viagra® and Cialis® in terms of duration of action?
What is a major difference between Viagra® and Cialis® in terms of duration of action?
Study Notes
Vasodilators
- Vasodilators are drugs that dilate blood vessels, decreasing blood pressure and increasing blood flow
- Classes of vasodilators include:
- Organic nitrates
- Potassium channel activators
- PDE5 inhibitors
Vascular Smooth Muscle Contraction and Relaxation
- Vascular smooth muscle contraction:
- Caused by calcium ions and calmodulin
- Leads to vasoconstriction
- Vascular smooth muscle relaxation:
- Caused by decreased calcium ions and increased cGMP
- Leads to vasodilation
Organic Nitrates
- Pharmacologic action: release NO, which increases cGMP, causing vasodilation
- Examples: nitroglycerin, isosorbide dinitrate (ISDN), isosorbide mononitrate (ISMN)
- MOA: donate NO, which activates guanylate cyclase, increasing cGMP
- ADRs: headache, dizziness, flushing, nausea
- Benefits: treat angina, heart failure, and hypertension
- Problems: nitrate tolerance, headaches, and dependence
Nitrate Tolerance and Management
- Mechanism: decreased ability of nitrates to release NO
- Management:
- Dose titration
- Nitrate-free periods
- Combination with other vasodilators
Potassium Channel Activators
- MOA: open potassium channels, leading to hyperpolarization and relaxation
- Drug names: nicorandil, pinacidil
- ADRs: headache, dizziness, hypotension
PDE5 Inhibitors
- MOA: inhibit phosphodiesterase 5, increasing cGMP
- Examples: sildenafil (Viagra), tadalafil (Cialis)
- ADRs: headache, flushing, dyspepsia
- Contraindications: nitrates, alpha-blockers
- Duration of action:
- Viagra: 4-6 hours
- Cialis: up to 36 hours
Viagra vs. Cialis
- Both PDE5 inhibitors
- Differences:
- Duration of action
- Onset of action
- Food effects
ISDN vs. ISMN
- Both organic nitrates
- Differences:
- Pharmacokinetics
- Dosing schedules
- ADR profiles
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Description
Test your knowledge on the use, classes, mechanisms, and pharmacological actions of vasodilators including organic nitrates, potassium channel activators, and PDE5 inhibitors. Learn about nitrate tolerance management and important drug names and adverse drug reactions.
