Vasodilators which are used in treatment of hypertension are divided into Arterial vasodilators, Venodilators and both ( arterial and veno- dilators ) .
A. Arterial vasodilators
- Now it has little place in the routine oral therapy.
- Used with pregnancy, it can be used in hypertensive encephalopathy by infusion .
- It leads to reflex increase in Heart rate which results in decreased coronary filling.
- Dose is up to 100 mg/day, in hypertensive emergency .
- Side effects :
- SLE like synd.
- Tachycardia - Headache - flushing .
Calcium channel blockers:
- Nifedipine 10-20mg /8hr .
- Amlodipine 5-10mg/d.
- Deltiazem 60-180mg/12hr.
- Verpami1120-480 mg/d .
- Very potent .
- Inhibits insulin release ((Used in insulinoma) .
- IV 1-3 mg/kg in cases of hypertensive encephalopathy it is given rapidly .
They are converted to nitric oxide which causes vasodilatation .
They can be used by infusion in case of hypertensive encephalopathy i.e glyceryl trinitrate (Tridil) 0.3-1 ug/kg/m .
- Oesophageal spasm and achalasia.
- Reliefe of pulmonary venous congestion .
- Myocardial infarction.
- Biliary colic and hypertensive encephalopathy.
Side effects: Headache - Hypotension
C. Arterial and Venodilators
- Very potent.
- Used in emergency ( H. encephalopathy , Cardiogenic pulmonary edema ) .
50 mg vial, start with 0.3-1 ug/kg/m, the control of blood pressure is established at 0.5-6 ug/kg/m ,maximum dose is 10 ug/kg/m.
Side Effects :
Hypotension, cyanide or thiocynate toxicity.
- Na nitroprusside converted to cyanide which is converted to thiocynate by the liver, thiocynate excreted in urine.
Liver disease: Cyanide toxicity. "Pink color, dilated pupil"
Renal disease: Thiocynate toxicity. "Tinitus, skin rash"
Alpha blockers : Discussed Here
Angiotensin Converting Enzyme Inhibitors ( ACE Inhibitors )
Side effects :
- Hyperkalemia, skin rash.
- Nephrotic syndrome (Membranous GN) .
- Dry cough due to accumulation of bradykinin in the lung .
- ACE inhibitors reduce the process of ventricular remodeling.
- ACE inhibitor contraindicated in bilateral renal artery stenosis.
OTHER ACE INHIBITORS:
- Ramipril 2.5-10 mg/d (Tritace).
- Lisinopril Long acting 10-20 mg/d (Zestril).
- Enalapril 10-20 mg/day oral (Ezapril), it can be given IV.
- Tranclolanril 1-4mg-/dav.
Angiotensin II Receptor Blockers (ARBs)
They include losatran 50-100 mg/D (Cozar) and valsartan 80-160 mg/D (Tareg) .