In canine hypertensive chorioretinopathy, which treatment combination is commonly used?

• A. Amlodipine alone
• B. Amlodipine and ACE-inhibitor
• C. Hydralazine
• D. ACE inhibitor alone

Answer: (B)

Controlling systemic blood pressure is the key in canine hypertensive chorioretinopathy because sustained high pressure damages the retina and choroid. Amlodipine lowers blood pressure by dilating peripheral arteries, reducing vascular resistance. An ACE inhibitor decreases angiotensin II production and aldosterone effects, adding further vasodilation and helping protect the kidneys. Using these together tackles hypertension through two different pathways, often achieving a greater and more stable reduction than either alone. This is important to slow or prevent ocular damage like retinal hemorrhages or detachment. While one drug alone may sometimes suffice, many cases need combination therapy to reach the target BP. Hydralazine is more suited for acute spikes and can cause reflex tachycardia, making it less ideal for chronic management, and an ACE inhibitor alone may not always bring the BP down sufficiently.