From Dog

Hydralazine is a protein kinase stimulator which increases cGMP levels, resulting in smooth muscle relaxation, vasodilation and hypotension of arteries and arterioles.

In dogs, it is primarily used to treat hypertension associated with congestive heart failure[1], particularly mitral valve endocardiosis in dogs[2], which develop side-effects with other drugs such as amlodipine[3].

This drug is well tolerated in most dogs although elevated levels of angiotensin and aldosterone have been reported, as well as hypokalemia and hyponatremia in long-term studies[4].

Recommended dose rate in dogs is 0.5 - 0.8 mg/kg given orally twice daily.


  1. Li D et al (2001) Effects of angiotensin-converting enzyme inhibition on the development of the atrial fibrillation substrate in dogs with ventricular tachypacing-induced congestive heart failure. Circulation 104(21):2608-2614
  2. Uehara Y & Takahashi M (1998) Hemodynamic changes during administration of drugs for mitral regurgitation in dogs. J Vet Med Sci 60(2):213-218
  3. Pariser MS & Berdoulay P (2011) Amlodipine-induced gingival hyperplasia in a Great Dane. J Am Anim Hosp Assoc 47(5):375-376
  4. Häggström J et al (1996) Effects of long-term treatment with enalapril or hydralazine on the renin-angiotensin-aldosterone system and fluid balance in dogs with naturally acquired mitral valve regurgitation. Am J Vet Res 57(11):1645-1652