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Vasodilators

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Vasodilators are a group of drugs prescribed to treat a heart condition. They are called vasodilators because – “vasa” stands for vessels and “dilator” means to make wider.

 

Mode of action

So how do they work?

The drugs relax the smooth muscles lining the walls of blood vessels, thereby causing the blood vessel to widen. As a result blood flows smoothly through the blood vessels and the tension on the walls of the vessel is relieved. The work load on the heart is lessened as blood pressure is lowered.


Why are they prescribed?

Vasodilators are prescribed to manage high blood pressure and not to cure it. They are prescribed under the following conditions:
  • Hypertension
  • Chest pain or angina
  • To relieve symptom of heart failure
  • Vascular migraines and panic attacks
  • Irregular heartbeat
  • High blood pressure during pregnancy (preeclampsia)

They are usually given in combination with other drugs

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Types of vasodilators

Vasodilators may act on veins, arteries or on both. Different types of vasodilators are:
  • ACE inhibitors (angiotensin-converting enzyme inhibitors): Angiotensin II is a chemical that causes narrowing of blood vessels.
  • ACE inhibitors block production Angiotensin II inside body to regularize blood flow inside arteries.
  • Angiotensin II receptor: They block the hormone angiotensin II from constricting the muscles lining the blood vessels but not its production. They bind to Ang II receptors as inhibitor· 
  • Alpha blockers oralpha-adrenergic antagonists: They prevent the hormone norepinephrine (noradrenaline) from tightening the muscles in the walls of smaller arteries and veins.
  • Calcium channel blockers: They prevent entry of calcium ions to large blood vessels by blocking the calcium channels.
  • Nitrates: They dilate the veins of the body, thereby increasing flow of oxygen-rich blood to the heart.
  • Central adrenergic inhibitors: They prevent the brain from transmitting signals to the nervous system to increase heart rate and tighten the blood vessels to tighten.
 
Recommended dosage and effectiveness of vasodilators

Vasodilators have been established as a successful medicine for managing high BP since quite a long period. The dosage of the drug depends on the type of vasodilator being used and if it should be taken with or without regard to food.


Side effects of vasodilators 

The side effects on vasodilators differ from one individual to other and they also depend how a person can deal with it. Some common side effects of vasodilators are:
  • Headache
  • Dizziness, light headedness
  • Increased or rapid heartbeat
  • Nausea, vomiting
  • Nasal congestion

The aforementioned side effects are temporary and they usually disappear as your body gets used to the dose. However, call your doctor right away if you experience difficulty in breathing, chest pain and joint pain, observe swelling in face, legs, lymph nodes, throat and lips or notice allergy (hives) and rashes on skin or any other unusual changes.

Points to remember while taking vasodilators
  • Vasodilators are not fist-line medicines for controlling high blood pressure. They are administered if other medicines fail and mostly as a combination drug
  • You need to fix follow up appointments during the initial period of dosage in order to know the response of your body
  • Ask your doctor how to deal with situations like overdose or missed dose. Do not consume the pill based on assumptions
  • Stick to the dosage and the timing of intake strictly. So ask your doctor for a simple schedule for the medicines
  • Let your doctor know if you are experiencing some abnormalities in health or gaining weight
  • Do not take any other pills either prescription or OTC, supplements, syrups, herbal drinks, etc. without consulting your doctor
  • Lastly, let your doctor know if you are pregnant, planning for pregnancy or if you are breastfeeding.

 

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ACE inhibitors

Written by: healthplus24.com team
Date last updated: Feburary 01, 2014