ACE inhibitors are a class of medications frequently used in veterinary medicine to support canine health, particularly in managing conditions that affect the heart and kidneys. These medications work by influencing certain systems within the body to improve organ function and overall well-being.
Understanding ACE Inhibitors
ACE stands for Angiotensin-Converting Enzyme. This enzyme is a key component of a complex biological system in the body called the Renin-Angiotensin-Aldosterone System (RAAS). The RAAS plays a significant role in regulating blood pressure, fluid balance, and electrolyte levels in dogs. When the body detects low blood pressure or reduced blood flow to the kidneys, it activates the RAAS to restore normal conditions.
Within the RAAS, a protein called angiotensinogen is converted into angiotensin I by an enzyme called renin. Angiotensin I is then transformed into angiotensin II by the Angiotensin-Converting Enzyme (ACE). Angiotensin II is a potent substance that causes blood vessels to narrow (vasoconstriction) and promotes the retention of sodium and water.
By blocking the ACE enzyme, ACE inhibitors prevent the formation of angiotensin II. This action leads to several beneficial effects, including the widening of blood vessels (vasodilation), which reduces the workload on the heart, and decreased retention of fluid and sodium. ACE inhibitors counteract the overactivation of the RAAS.
Why Vets Prescribe ACE Inhibitors for Dogs
Veterinarians commonly prescribe ACE inhibitors for dogs to manage several medical conditions that benefit from their effects on blood pressure and fluid balance. One primary use is in the treatment of congestive heart failure (CHF), often resulting from conditions like myxomatous mitral valve disease (MMVD) or dilated cardiomyopathy (DCM). In CHF, the heart struggles to pump blood effectively, leading to fluid buildup in the lungs and other body tissues. By promoting vasodilation and reducing fluid retention, ACE inhibitors ease the heart’s workload and help to reduce fluid accumulation, improving clinical signs and potentially increasing survival time.
Another important application is in chronic kidney disease (CKD), particularly when there is protein loss in the urine, a condition known as proteinuria. In CKD, the kidneys’ ability to filter waste is compromised, and proteinuria indicates damage to the kidney’s filtering units. ACE inhibitors help reduce protein loss by decreasing pressure within the kidney’s filtering structures and improving blood flow, thereby protecting kidney function and potentially delaying disease progression. These medications are also used to manage systemic hypertension (high blood pressure) in dogs. While ACE inhibitors can help manage blood pressure, they are often a first-line treatment or used in combination with other medications to achieve target blood pressure levels, especially in dogs with concurrent kidney issues.
Giving Your Dog ACE Inhibitors and What to Watch For
Administering ACE inhibitors to your dog involves giving oral tablets, often prescribed for once or twice daily dosing. Consistency in dosing time is recommended, and these medications can be given with or without food. If your dog experiences an upset stomach when given the medication on an empty stomach, providing it with food or a treat might help. Ensure your dog has access to fresh water, as these medications can increase thirst.
While ACE inhibitors are well-tolerated, pet owners should be aware of potential side effects and monitor their dog closely. Common side effects include gastrointestinal upset such as vomiting, diarrhea, or a decreased appetite. Some dogs may also exhibit lethargy, weakness, or dizziness, which could indicate low blood pressure (hypotension). Changes in kidney function can occur, and your veterinarian will monitor this through regular blood tests.
Contact your veterinarian immediately if you observe any concerning signs, such as severe lethargy, collapse, persistent vomiting or diarrhea, or significant changes in thirst or urination. These signs may indicate a need for dosage adjustment or further evaluation.
Managing Your Dog’s Treatment
Ongoing management for dogs receiving ACE inhibitors involves regular veterinary check-ups to monitor their health and the medication’s effectiveness. These appointments include blood tests to assess kidney function (BUN and creatinine levels) and electrolyte levels, particularly potassium. Blood pressure monitoring is also a routine part of this management, especially if your dog has a history of hypertension or shows signs of low blood pressure. Your veterinarian will use these results to ensure the medication is working as intended and to make any necessary dosage adjustments.
Inform your veterinarian about all other medications, supplements, or herbal remedies your dog is receiving, as some can interact with ACE inhibitors. For example, concurrent use with non-steroidal anti-inflammatory drugs (NSAIDs) can increase the risk of kidney issues. Combining ACE inhibitors with certain diuretics or potassium supplements may increase the risk of elevated potassium levels in the blood. If a dose is missed, it should be given as soon as remembered unless it is almost time for the next scheduled dose, in which case the missed dose should be skipped; double doses should never be given. ACE inhibitors are part of a long-term treatment plan for chronic conditions, and consistent adherence to the prescribed regimen and veterinary recommendations is important to managing your dog’s health.