Page 1020 - Cote clinical veterinary advisor dogs and cats 4th

502 Hypertension, Systemic

If evidence of ocular or neurologic TOD Cats with systolic BP > 200 mm Hg
■ ■ PROGNOSIS & OUTCOME
is present, reduce systolic BP by 25% may benefit from beginning doses of • If retinal detachment (p. 885) has occurred,
VetBooks.ir to < 160 mm Hg recommended by 6 ○ ACEIs are usually inadequate as mono- the retina may reattach with good control of
1.25 mg PO q 24h per cat, regardless
in the first 1-2 hours, with reduction
of weight.
BP, but prognosis for return of vision varies.
hours after beginning therapy.
○ Second priority: initiate clinical evaluation
for causative disease therapy but may have additive effects • Prognosis for resolution of other clinical signs
of hypertension (e.g., focal facial seizures,
when given with other medications or if
• SH found in conjunction with causative proteinuria is present. changes in mentation) is favorable if BP
underlying disease but no clinical signs of ■ Enalapril 0.5 mg/kg PO q 12-24h can be controlled with medication and with
hypertension are present ■ Benazepril 0.25-0.5 mg/kg PO q 24h effective therapy of underlying diseases.
○ Institute optimal therapy of causative ■ Beta-blockers are unlikely to be effective • Prognosis for SH may be affected by prog-
condition. as monotherapy for SH. nosis for causative disease.
○ Confirm elevated BP values on more than
one occasion to lessen the chance of false- Drug Interactions PEARLS & CONSIDERATIONS
positive due to anxiety- or excitement- • BP-lowering sedatives (e.g., acepromazine)
related elevations of BP. Confirmatory BP should be used with caution in animals Comments
measurements can be performed several receiving any antihypertensive medication. • SH is likely to be progressive over time
hours to several days later. • Two medications from the same drug group in dogs even if initially well-controlled on
○ If systolic BP > 180 mm Hg on more than should not be used together (e.g., benazepril medications. Monitoring BP during long-
one measurement occasion (preferably and enalapril). term therapy allows detection of progression
same day), begin antihypertensive therapy. of SH during therapy.
○ Systolic BP is 160-180 mm Hg on more Possible Complications • SH usually remains controlled in treated cats
than one measurement occasion • Hypotension and is seldom progressive, but monitoring
If underlying disease can be controlled ○ Resuscitate as needed; supportive fluid over time is still required as changes in
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or cured, monitor BP during therapy of therapy may be necessary. weight (especially decreases) might lead to
underlying disease, and treat if systolic ○ Reduce dose of BP medication. hypotension if therapy is not adjusted.
BP continues to exceed 160 mm Hg ○ Re-evaluate need for antihypertensive
after optimal therapy of underlying medication or reduce dose if weight loss Technician Tips
disease. has occurred. • Owners may interpret clinical signs of
If underlying disease is unknown or • Uncontrolled hypertension despite drug hypertension (e.g., lethargy, drowsiness)
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unlikely to be cured (e.g., CKD), begin therapy as signs of aging, and vigilance regarding
antihypertensive therapy. ○ Check compliance: review medications and monitoring of BP in animals at risk can
administration information with caregiver. detect subclinical cases.
Acute General Treatment ○ Check BP measurement technique (i.e., • Any dog or cat with a systemic disease known
• Discontinue any hypertensive medications. cuff size, inadequate period of acclimation). to cause hypertension should have its BP
• Emergency antihypertensive therapy for ○ Add medications from other classes if monitored periodically regardless of clinical
animals with acute ocular or neurologic signs needed. signs.
○ Dogs, oral or IV therapy (start at low end ○ Consult a specialist for further additions/ • High BP detected in young animals with
of dose and titrate to effect). modifications if hypertension is not no risk factors is often spurious.
Nitroprusside 0.5-5 mcg/kg/min as controlled with two antihypertensive • Pet owners may be taught to assess BP at
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continuous rate infusion IV, or medications at upper end of dosing ranges. home for chronic monitoring.
Hydralazine (oral) 0.5-2 mg/kg PO q • Previously controlled hypertension now out
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12h of desired target range Client Education
○ Cats ○ Dogs: hypertension may worsen over time, • For optimal patient management, inform
Amlodipine 0.625 mg PO q 24h if or underlying disease may be inadequately clients that
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cat ≤ 5 kg; 1.25 mg PO q 24h if cat controlled: ○ Hypertension is usually a complication
> 5 kg, or ■ Ensure optimal therapy of underlying of another disease rather than primary
Hydralazine 0.5-2 mg/kg PO q 12h disease. disease in itself.
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■ Screen for hypertensive medications ○ Control of hypertension is necessary to
Chronic Treatment ■ Check post-pill serum thyroxine con- avoid catastrophic ocular or neurologic
• Dogs centration in animals receiving thyroid damage and to minimize ongoing damage
○ Transition from nitroprusside or hydrala- supplementation. to susceptible organs (e.g., kidneys).
zine to amlodipine is recommended for ■ Add additional antihypertensive medica- ○ If the underlying disease is not curable,
chronic therapy. tions or increase doses of current medi- therapy for SH is likely to be lifelong.
Amlodipine 0.2-0.4 mg/kg PO q 24h cations to high end of dosage range if ○ Many patients require more than one
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○ Angiotensin-converting enzyme inhibitors tolerated. medication to adequately control hyper-
(ACEIs) can be added if proteinuria is ○ Cats: hypertension control is usually stable tension, and the need for medication may
present or if amlodipine alone is inad- once achieved. If BP continues to increase increase over time.
equate to control BP. ACEIs as mono- over time, treat as recommended above.
therapy can be expected to lower systolic SUGGESTED READING
BP by approximately 10%. Recommended Monitoring Acierno MJ, et al: ACVIM consensus statement:
Enalapril 0.5 mg/kg PO q 12-24h, or • After the underlying condition and SH are
■ guidelines for the identification, evaluation, and
Benazepril 0.25-0.5 mg/kg PO q 12-24h controlled, check BP in patients receiving management of systemic hypertension in dogs and
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• Cats antihypertensive therapy every 3 months. cats. J Vet Intern Med 32(6):1803-1822, 2018.
○ Calcium channel blockers (preferred • If doses/medications change, recheck BP in AUTHOR: Rebecca L. Stepien, DVM, MS, DACVIM
first-line therapy) 3-5 days after change to ensure efficacy. EDITOR: Meg M. Sleeper, VMD, DACVIM
Amlodipine 0.625 mg PO q 24h if cat • Monitor weight at each visit to avoid accidental
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≤ 5 kg; 1.25 mg PO q 24h if cat > 5 kg overdose if weight loss has occurred.
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