Pharmacology NCM 106 Quiz

Infusion Basics

• Infusion of 1000 mL PNSS over 4 hours indicates a steady administration of fluids for patient hydration or electrolyte balance.
• Alternative infusion of 250 mL PNSS over 5 hours provides a slower delivery of fluids, useful for specific patient needs.

Drug Receptor Types

• Agonists: Activate receptors to produce physiological effects.
• Antagonists: Block receptor activation by agonists, resulting in oppositional effects.

Alpha Receptors

• Alpha 1 Receptors: Located mainly in blood vessels; activation causes vasoconstriction, which increases blood pressure.
• Alpha 2 Receptors: Found in blood vessels; their activation leads to vasodilation, reducing blood pressure.

Beta Receptors

• Beta 1 Receptors: Primarily in heart muscles; stimulation increases heart rate (tachycardia) and may elevate respiratory rates and blood pressure.
• Beta 2 Receptors: In airway smooth muscles; activation results in bronchodilation, widening airways which benefits conditions like asthma.

Antihypertensive Medications

• Antagonists can have significant effects on blood pressure regulation by blocking specific receptor pathways.

Antagonist Effects and Interactions

• Alpha 1 Antagonists: Cause vasodilation, thus lowering blood pressure due to relaxed blood vessels.
• Alpha 2 Antagonists: Block vasodilation, leading to vasoconstriction and increased blood pressure.
• Beta 1 Antagonists: Slow heart rate and might weaken heart contractions. Commonly prescribed for hypertension and heart conditions.

Specific Drugs and Their Effects

• Selective Alpha 1 (e.g., Prazosin): Used for hypertension without significant glucose impact, beneficial for diabetic patients.
• Non-selective Beta Blockers (e.g., Propranolol): Affect both Beta 1 and Beta 2, reducing heart rate and contractility.

Side Effects and Considerations

• High doses of Alpha 2 antagonists may cause sodium and water retention, leading to peripheral edema.
• Caution is advised with beta-blockers when taken alongside alcohol and other antihypertensives.
• Beta 2 antagonism can result in bronchoconstriction, worsening breathing conditions like asthma.

Clinical Monitoring

• Blood pressure should be monitored 15 minutes after sublingual administration of medications, particularly in acute care settings.

Hypertensive Crisis

• Defined as systolic blood pressure higher than 180 mmHg; situations involving reflex tachycardia and demands careful management to prevent complications.

Summary

• Antihypertensive medications manipulate various adrenergic receptor pathways for desired cardiovascular outcomes; understanding their mechanisms is crucial for effective clinical practice.