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Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

 Rational combination

1- Organic Nitrates and β-Adrenergic Receptor Blockers

 Nitrates (VD) →reflex tachycardia → myocardial oxygen demand # by
combination with beta Bs (bradycardia).

 β receptor blockers → coronary vasospasm while nitrates (coronary vasodilation)
and thus may prevent this undesirable effect of beta-blockade.

2+
2- Ca Channel Blockers and β- Blockers

 Nifedipine or amlodipine → reflex tachycardia while BBs→bradycardia (side effect
overcome the other)→ Beneficial interaction

 Verapamil and diltiazem → bradycardia & -ve inotropic, and BBs → bradycardia
and –ve inotropic (addition in side effects) → irrational combination.

2+
3- Ca Channel Blockers and Nitrates

 All CCBs → afterload, while nitrates → preload → significant reductions in

myocardial oxygen requirement. However, hypotension with excessive vasodilation
are adverse effects. (irrational combination). Need adjustment of dose to be applied

 Triple Therapy
2+
(Ca Channel Blockers + Nitrates + β- Blockers)

 Rationale: CCBs dihydropyridine ( afterload) + nitrates (preload) + βBs (

contractility and heart rate).

 Irrational: Diltiazem and verapamil + βBs + nitrates (severely compromise cardiac

functions).

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