AFPI Karnataka Newsletter

Issue: Volume 5, Issue 1

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Vasodilators in clinical day to day practice

Dr L Padma (MBBS, MD, Dip. in Diabetology, Practical Cardiology and Geriatric Care)

Vasodilators are drugs which are useful in the management of hypertension, angina, heart failure, MI, preeclampsia, hypertensive emergencies etc.

The different classes of vasodilators used in current clinical practice has different actions on the coronary arteries and peripheral vasculature on both arteries and veins. Vasodilators more commonly affect the arteries but some vasodilators such as nitro-glycerine can affect the venous system predominantly.

Table 1: Vasodilators and uses. View in new window

DrugsMechanism Of ActionAdverse EffectsContraindicationsUses
Directly acting vasodilatorsVenousNitrates (GTN and Nitroglycerin)Releases NO through cyclic GMPTachycardia, headache, flushing and orthostatic hypotensionAs they decrease preload do not use in inferior MI or right ventricular infarctionAcute and chronic angina
ArterialCCB (DHP like Amlodipine and non-DHP like Verapamil)Blocks calcium channels in the cardiac and smooth muscleGingival hyperplasia and peripheral edema, AV block, bradycardia and constipationHypotension and hypersensitivityHTN, arrythmia, angina
Minoxidil, DiazoxideATP sensitive potassium channel openersHypertrichosis, Fluid retentionAlopecia
PrazosinAlpha BlockerFirst dose hypotensionCHF3rd line drug in HTN
HydralazineDirectly relaxes arteriolar smooth muscles through cyclic AMPTachycardia, fluid retention and SLECAD, angina, RHD as it causes compensatory tacchycardiaPIH
MixedACE inhibitorsPrevent conversion of Angiotensin I to IIDry cough hyperkalemia and hypotensionPregnancy and hereditary angioedemaHeart failure, HTN, MI, CCF, Scleroderma crisis
ARBPrevents Angiotensin II from binding to its receptor (cardio-reno protective)Hyperkalemia and hypotensionPregnancy
Sodium NitroprussideBoth venous and arteriolar dilator releasing NOCyanide toxicityHypertensive emergencies
Beta 2 receptor agonistSalbutamol TerbutalineBeta 2 mediated vasodilatationTremors hypokalemia
Centrally acting Alpha 2 receptor agonistClonidine, MethyldopaActs on presynaptic alpha 2 receptor and decreases sympathetic outflowRebound hypertension on withdrawalClonidine - Last Drug Of Choice In HTN
Methyldopa - First drug of choice in PIH but nowadays we are into “Nifedipine Retard or Labetelol”
Endothelin receptor antagonistsBosentan, AmbrisentanETA and ETB receptor blockerAnaemia, teratogenecityPulmonary arterial hypertension
Beta Blockers with Nitric Oxide vasodilatationBisoprolol, NebivololBeta 1 block reduces heart rate and cardiac work load and NO causes vasodilatationBradycardiaHeart BlockYoung hypertensives

Clinical Pearls

  1. Educate the patient about adverse effects
  2. Importance of taking their vasodilator medication as prescribed
  3. Under treatment or non compliance can cause severe hypertension and complications which are preventable
  4. Ask the patient to inform if they have missed or want to stop the treatment
  5. Educate LSM, plant based eating habits, 10,000 steps per day aerobic excercises, and avoid smoking, alcohol and recreational drugs
  6. Clinical pharmacologist should assist in selection, dosing, medication reconciliation and patient education