Vasodilators: Difference between revisions

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==== Pharmacodynamics ====
==== Pharmacodynamics: ====
The drug class of vasodilators treat hypertension by directly vasodilating blood vessels in the periphery. Vasodilators decrease resistance in the blood vessels resulting in a decrease in blood pressure (Walter, Waldmann, & Nieberding, 1988). Direct-acting vasodilators dilate arterioles specifically, without having a dilating effect on the venous system (Cohn, Mcinnes, & Shepherd, 2011). Although, many antihypertensive drugs ultimately produce vasodilation through a cascade of events, this class antihypertensive drugs produce vasodilation by acting directly on the smooth muscle of the vasculature in the periphery (pharmacotherapy Hypertension carter ) Specifically, direct-acting vasodilators stimulate intracellular components by activating phosphorylation of cyclic-adenosine monophosphate (cAMP) and cyclic-guanosine monophosphate (cGMP) (Walter, Waldmann, & Nieberding, 1988). These cyclic second-messengers inhibit smooth muscle contraction, as well as platelet aggregation (Walter, Waldmann, & Nieberding, 1988).  
The drug class of vasodilators treat hypertension by directly vasodilating blood vessels in the periphery. Vasodilators decrease resistance in the blood vessels resulting in a decrease in blood pressure.<ref name=":0">Walter U, Waldmann R, Nieberding M. Intracellular mechanism of action of vasodilators. ''European Heart Journal''. 1988;9(suppl H):1-6. doi:10.1093/eurheartj/9.suppl_h.1.</ref> Direct-acting vasodilators dilate arterioles specifically, without having a dilating effect on the venous system.<ref name=":1">Cohn JN, Mcinnes GT, Shepherd AM. Direct-Acting Vasodilators. ''The Journal of Clinical Hypertension''. 2011;13(9):690-692.
</ref> Although, many antihypertensive drugs ultimately produce vasodilation through a cascade of events, this class antihypertensive drugs produce vasodilation by acting directly on the smooth muscle of the vasculature in the periphery. <ref>Carter B, Saseen J. ''Hypertension''. 5th ed. New York , NY: McGraw-Hill; 2002.</ref> Specifically, direct-acting vasodilators stimulate intracellular components by activating phosphorylation of cyclic-adenosine monophosphate (cAMP) and cyclic-guanosine monophosphate (cGMP).<ref name=":0" /> These cyclic second-messengers inhibit smooth muscle contraction, as well as platelet aggregation. <ref name=":0" />


==== Pharmacokinetics ====
==== Pharmacokinetics: ====
However, direct vasodilators are usually not the first in line in the treatment of hypertension. This class of drugs have a fairly short half-life, which requires frequent doses throughout the day (Patel & Jneid, 2018). This class of drugs are primarily metabolized by the liver and excreted via the kidneys (Cohn, Mcinnes, & Shepherd, 2011). While vasodilators are successful in controlling hypertension, these medications possess a myriad of side effects. Reflex tachycardia is the primary adverse effect of these drugs, as a consequence of the medication induced baroreflex response compensating for the sudden medication decrease in vascular resistance. Other less serious side effects include orthostatic hypotension, dizziness, weakness, fluid retention and nausea (Ciccone, 2016). PTs should be mindful of potential implications of adverse effects of these drugs or contraindications to therapy in patients.  
However, direct vasodilators are usually not the first in line in the treatment of hypertension. This class of drugs have a fairly short half-life, which requires frequent doses throughout the day.<ref>Patel P, Jneid H. Interventional Pharmacology-Vasodilators. The Cardiology Advisor. <nowiki>https://www.thecardiologyadvisor.com/cardiology/interventional-pharmacologyvasodilators/article/583886/</nowiki>. Published September 17, 2018. Accessed October 10, 2018.</ref> This class of drugs are primarily metabolized by the liver and excreted via the kidneys.<ref name=":1" /> While vasodilators are successful in controlling hypertension, these medications possess a myriad of side effects. Reflex tachycardia is the primary adverse effect of these drugs, as a consequence of the medication induced baroreflex response compensating for the sudden medication decrease in vascular resistance. Other less serious side effects include orthostatic hypotension, dizziness, weakness, fluid retention and nausea.<ref>Ciccone CD. ''Pharmacology in Rehabilitation''. 5th ed. Philadelphia: F.A. Davis Company; 2016.
</ref> PTs should be mindful of potential implications of adverse effects of these drugs or contraindications to therapy in patients.  


Back to [[Pharmacological management of Hypertension|Pharmacological Management of Hypertension]]
Back to [[Pharmacological management of Hypertension|Pharmacological Management of Hypertension]]


==== References ====
==== References ====

Revision as of 20:50, 29 November 2018

Pharmacodynamics:[edit | edit source]

The drug class of vasodilators treat hypertension by directly vasodilating blood vessels in the periphery. Vasodilators decrease resistance in the blood vessels resulting in a decrease in blood pressure.[1] Direct-acting vasodilators dilate arterioles specifically, without having a dilating effect on the venous system.[2] Although, many antihypertensive drugs ultimately produce vasodilation through a cascade of events, this class antihypertensive drugs produce vasodilation by acting directly on the smooth muscle of the vasculature in the periphery. [3] Specifically, direct-acting vasodilators stimulate intracellular components by activating phosphorylation of cyclic-adenosine monophosphate (cAMP) and cyclic-guanosine monophosphate (cGMP).[1] These cyclic second-messengers inhibit smooth muscle contraction, as well as platelet aggregation. [1]

Pharmacokinetics:[edit | edit source]

However, direct vasodilators are usually not the first in line in the treatment of hypertension. This class of drugs have a fairly short half-life, which requires frequent doses throughout the day.[4] This class of drugs are primarily metabolized by the liver and excreted via the kidneys.[2] While vasodilators are successful in controlling hypertension, these medications possess a myriad of side effects. Reflex tachycardia is the primary adverse effect of these drugs, as a consequence of the medication induced baroreflex response compensating for the sudden medication decrease in vascular resistance. Other less serious side effects include orthostatic hypotension, dizziness, weakness, fluid retention and nausea.[5] PTs should be mindful of potential implications of adverse effects of these drugs or contraindications to therapy in patients.

Back to Pharmacological Management of Hypertension

References[edit | edit source]

  1. 1.0 1.1 1.2 Walter U, Waldmann R, Nieberding M. Intracellular mechanism of action of vasodilators. European Heart Journal. 1988;9(suppl H):1-6. doi:10.1093/eurheartj/9.suppl_h.1.
  2. 2.0 2.1 Cohn JN, Mcinnes GT, Shepherd AM. Direct-Acting Vasodilators. The Journal of Clinical Hypertension. 2011;13(9):690-692.
  3. Carter B, Saseen J. Hypertension. 5th ed. New York , NY: McGraw-Hill; 2002.
  4. Patel P, Jneid H. Interventional Pharmacology-Vasodilators. The Cardiology Advisor. https://www.thecardiologyadvisor.com/cardiology/interventional-pharmacologyvasodilators/article/583886/. Published September 17, 2018. Accessed October 10, 2018.
  5. Ciccone CD. Pharmacology in Rehabilitation. 5th ed. Philadelphia: F.A. Davis Company; 2016.