Page 245 - Small Animal Internal Medicine, 6th Edition

CHAPTER 11 Systemic Arterial Hypertension 217

TABLE 11.1
VetBooks.ir Drugs Used to Treat Hypertension DOG CAT

DRUG

ACEIs (see Chapter 3)
Enalapril 0.5 mg/kg PO q12h 0.5 mg/kg PO q24h
Benazepril 0.5 mg/kg PO q12h Same
Ramipril 0.125-0.25 mg/kg PO q24h 0.125 mg/kg PO q24h
Captopril 0.5-2 mg/kg PO q8-12h 0.5-1.25 mg/kg PO q(8-)24h

Calcium Channel Blocker
Amlodipine 0.1-0.3 (up to 0.5) mg/kg PO q24(-12)h 0.625 mg/cat (or 0.1-0.2 [up to 0.5]
mg/kg) PO q(-12)24h
β-Adrenergic Blockers (see Chapter 4)
Atenolol 0.2-1 mg/kg PO q12(-24)h (start low) 6.25-12.5 mg/cat PO q12(-24)h
Propranolol 0.1-1 mg/kg PO q8h (start low) 2.5-10 mg/cat PO q8-12h
α 1 -Adrenergic Blockers
Phenoxybenzamine 0.25 mg/kg PO q8-12h or 0.5 mg/kg q24h 2.5 mg/cat PO q8-12h or 0.5 mg/kg
q12-24h
Prazosin 0.05-0.2 mg/kg PO q8-12h 0.25-0.5 mg/cat PO q12-24h
Drugs for Hypertensive Crisis
Amlodipine 0.1-0.3 (up to 0.5) mg/kg PO q24(-12)h 0.625 mg/cat (or 0.1-0.2 [up to 0.5]
mg/kg) PO q(-12)24h
Hydralazine (see Chapter 3) 0.5-2 mg/kg PO q12h (start low, titrate up to Same (or 2.5 [up to 10] mg/cat PO
effect); or 0.1-0.2 mg/kg, IV or IM, repeat q12h)
q2h as needed
Nitroprusside (see Chapter 3) 0.5-1 mcg/kg/min CRI (initial) to 5-15 mcg/ 0.5-1 mcg/kg/min CRI (initial), to
kg/min CRI 5 mcg/kg/min CRI
Esmolol 25-75 (up to 200) mcg/kg/min CRI Same
Propranolol 0.02 mg/kg (initial) to max of 0.1 mg/kg slow Same
IV
Acepromazine 0.05-0.1 mg/kg (up to 3 mg total) IV 0.01-0.05 mg/kg IV
Phentolamine 0.02-0.1 mg/kg IV bolus, followed by CRI to Same
effect

ACEI, Angiotensin-converting enzyme inhibitor; CRI, constant-rate infusion; IV, intravenous; PO, by mouth.

be tried. Continued attention to the underlying disease steroids, and erythropoietin) can exacerbate hypertension or
process is important. Routine CBC, serum biochemistry complicate its control. Target-organ damage from systemic
profile, and urinalysis (with UPC) are also recommended hypertension could improve or reverse once patients become
every 6 months. Other tests are done as indicated. Decreas- normotensive. Retinal hemorrhage generally resolves and
ing the magnitude of proteinuria associated with hyperten- detached retinas may reattach, although prognosis for vision
sion is a desired treatment outcome, as degree of proteinuria remains guarded. Reverse remodeling of LV hypertrophy can
is a negative prognostic factor in cats with CKD. occur. Adequate control of BP also is thought to decrease the
The long-term prognosis for animals with hypertension rate of progression of CKD.
reflects prognosis for the underlying disease, which may
be chronic and progressive. Unfortunately, hypertension ANTIHYPERTENSIVE DRUGS
often persists even with adequate treatment or control of The ACEIs (e.g., enalapril, benazepril) reduce angiotensin
the underlying disease, particularly in dogs with hyperad- II production, thereby reducing vascular resistance and
renocorticism and cats with hyperthyroidism. In addition, volume retention (see p. 67). These agents also selectively
therapy for some primary diseases (such as fluid therapy, dilate the glomerular efferent arteriole and thus decrease