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== Introduction ==
== Introduction ==
[[File:Vasoconstriction and Vasodilation.png|thumb]]
[[File:Vasoconstriction and Vasodilation.png|right|frameless|350x350px]]
Vasodilators are medicines that dilate blood vessels thus blood to flow more easily through. Some act directly on the smooth [[muscle]] cells lining the blood vessels. Other have a central effect, and regulate blood pressure most likely through the vasomotor center located within the [[Brainstem|medulla oblongata]] of the brain.<ref>Drugs.com [https://www.drugs.com/drug-class/vasodilators.html Vasodilators] Available from: https://www.drugs.com/drug-class/vasodilators.html (last accessed 20.6.2019)</ref>
Vasodilators are medicines that dilate blood vessels allowing blood to flow more easily through.  
* Some act directly on the smooth [[muscle]] cells lining the [[Cardiovascular System|blood vessels]].  
* Some have a central effect, and regulate [[Blood Pressure|blood pressure]] most likely through the vasomotor center located within the [[Brainstem|medulla oblongata]] of the brain.<ref>Drugs.com [https://www.drugs.com/drug-class/vasodilators.html Vasodilators] Available from: https://www.drugs.com/drug-class/vasodilators.html (last accessed 20.6.2019)</ref>


== 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.<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.
The drug class of vasodilators treat hypertension by directly vasodilating blood vessels in the periphery.  
</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" />  
* 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>  
* 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 and Adverse Effects: ==
== Pharmacokinetics and Adverse Effects  ==
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|orthostatic hypotension,]] dizziness, weakness, fluid retention and nausea.<ref>Ciccone CD. ''Pharmacology in Rehabilitation''. 5th ed. Philadelphia: F.A. Davis Company; 2016.
Direct vasodilators are usually not the first in line in the treatment of hypertension.
</ref> PTs should be mindful of potential implications of adverse effects of these drugs or contraindications to therapy in patients.  
 
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>
* 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|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.  


See also [[Pharmacological Management of Hypertension|Pharmacological Management of Hypertension]]
See also [[Pharmacological Management of Hypertension|Pharmacological Management of Hypertension]]

Revision as of 07:52, 26 September 2020

Original Editor - Rachael Williams Top Contributors - Lucinda hampton, Kim Jackson, Rachel Williams and Adam Vallely Farrell

Introduction[edit | edit source]

Vasoconstriction and Vasodilation.png

Vasodilators are medicines that dilate blood vessels allowing blood to flow more easily through.

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.[2]
  • Direct-acting vasodilators dilate arterioles specifically, without having a dilating effect on the venous system.[3]
  • 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.[4]
  • Specifically, direct-acting vasodilators stimulate intracellular components by activating phosphorylation of cyclic-adenosine monophosphate (cAMP) and cyclic-guanosine monophosphate (cGMP).[2] These cyclic second-messengers inhibit smooth muscle contraction, as well as platelet aggregation.[2]

Pharmacokinetics and Adverse Effects[edit | edit source]

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.[5]
  • Primarily metabolized by the liver and excreted via the kidneys.[3]

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.[6]

PTs should be mindful of potential implications of adverse effects of these drugs or contraindications to therapy in patients.

See also Pharmacological Management of Hypertension

References:[edit | edit source]

  1. ↑ Drugs.com Vasodilators Available from: https://www.drugs.com/drug-class/vasodilators.html (last accessed 20.6.2019)
  2. ↑ 2.0 2.1 2.2 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.
  3. ↑ 3.0 3.1 Cohn JN, Mcinnes GT, Shepherd AM. Direct-Acting Vasodilators. The Journal of Clinical Hypertension. 2011;13(9):690-692.
  4. ↑ Carter B, Saseen J. Hypertension. 5th ed. New York , NY: McGraw-Hill; 2002.
  5. ↑ 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.
  6. ↑ Ciccone CD. Pharmacology in Rehabilitation. 5th ed. Philadelphia: F.A. Davis Company; 2016.
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