Experienced and professional animal trainer provide their insights in answering this question :
A. Yes it would and it is not a safe medication to use in elderly dogs, it can lower the blood pressure and cause life threatening side effects.

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Common: Acepromazine will cause hypotension, decreased respiratory rate, and bradycardia. Dogs are particularly sensitive to cardiovascular side-effects but cardiovascular collapse also has occurred in cats.
Drugs for Long-term Anxiety Issues

Side effects vary, but common ones include stomach upset, heart rate changes, sedation, or excitability. These drugs must be avoided or used cautiously in dogs with certain underlying health conditions.

Toxicity to pets

When accidentally ingested in poisonous amounts by pets, ACE inhibitors can result in hypotension (low blood pressure), lethargy, weakness, vomiting, and diarrhea.

Acepromazine FAQs

When the oral version of acepromazine is used for sedation or other stressful events, it is estimated to last approximately 1-4 hours. However, this medication can last for up to 24 hours after administration in some pets.

Most acepromazine poisonings occur in curious children or when people unintentionally mistake it for their own medication. Common symptoms of acepromazine poisoning include drowsiness and slowed breathing. In some cases, seizures, coma, and death have been reported.
Benzodiazepines are a class of sedatives typically used in dogs (and people) to treat anxiety, to address behavioral issues, and to relax muscles or suppress seizure activity. When used as directed by a veterinarian, they can be very effective. But they can be toxic if swallowed at higher doses.
Certain dogs have a higher anesthetic risk due to their breed, size, health, or age. These risks can run from minor problems, such as mild vomiting after recovery from anesthesia to life-threatening problems such as cardiac arrest or stroke.
Are there any potential side effects? The most common and important side effect of acepromazine use is low blood pressure, and in severe cases, it can cause cardiovascular collapse. In cats, it can also decrease tear production.
Dosage and Administration

Dogs: 0.25-1.0 mg/lb of body weight.

Dosing Information of Acepromazine for Dogs and Cats

The usual oral dose of acepromazine is 0.5 to 1.5 mg per pound (1 to 3 mg/kg). The usual injectable dose is 0.01 to 0.1 mg per pound (0.02 to 0.2 mg/kg). Generally, the injectable dose should not exceed 3 mg total.

Your pet has been sent home with Acepromazine. This is a very strong tranquilizer, and the intent of its use is to calm your pet, making her/him more content being less active in the post-operative phase of her/his rehabilitation.
Clinical significance: Doxapram is effective in reducing the sedative effects of acepromazine over a short period of time. A dose of 1·25 mg/kg effectively decreases acepromazine sedation without causing panting.
Acepromazine caused significant decreases in arterial blood pressure, stroke volume, left ventricular work, left ventricular stroke work, breathing rate, minute ventilation, and oxygen consumption.
The typical dog sedation recovery time is generally within 12 to 48 hours provided everything went smoothly. If the anaesthesia is expected to take longer to wear off, your vet will inform you.
Medications used to tranquilize animals can produce unintended side effects. However, airlines and professional pet transport companies forbid any form of sedation because it increases health and safety risks for dogs and cats. Sedated animals lose muscle control and cannot maintain their balance.
Measurements and main results: The frequency of seizures was 14% (CI: 3.6-24.3%) and 13.0% (CI: 0.7-27%) in dogs that received methadone/acepromazine and methadone alone, respectively.
Acepromazine is a member of the class of phenothiazines that is 10H-phenothiazine substituted by an acetyl group at position 2 and a 3-(dimethylamino)propyl group at position 10. It has a role as a phenothiazine antipsychotic drug.
Although anesthesia is never without risk, older pets who are in good physical condition can undergo anesthesia with no complications. Sometimes, however, an older pet with a pre-existing health condition requires surgery, and specialized care.
A 14-year-old dog is not too old for surgery, but older dogs may have more health issues that require surgical intervention. For example, if the dog has significant medical problems, such as arthritis, tumors, or a debilitating condition like heart disease, then surgery may be required to address those conditions.
The heart and lungs will stop functioning within minutes after injecting the euthanasia solution, so dogs generally won`t feel pain because they are unconscious. They may react to the procedure by having muscle spasms or crying out due to underlying sickness, yet the whole process is quick, simple, and painless.
Though it is used as an anti-anxiety medication, there are indications that while it may stabilize heart function, it does not actually suppress anxiety.
Side effects that your pet may exhibit while on Acepromazine are: altered breathing patterns, shivering, blood shot eyes, and protrusion of the third eyelid (a pink fleshy eyelid that people don`t have, in the inner corner of the eye socket).
What side effects are associated with acepromazine? Acepromazine may cause excessive sedation, abnormal gait (walking as if drunk, unstable on feet), and decreased blood pressure. Elevation of the third eyelid is a common and normal occurrence with the use of acepromazine.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. Would !/2 of a 25mg acepromazine be too much for a 13yr old shih zui wieght 18jbs for grooming?
ANSWER : A. Yes it would and it is not a safe medication to use in elderly dogs, it can lower the blood pressure and cause life threatening side effects.

Q. My 12 year old Border Collie/healer mix has a baseball size hematoma under her chest. I am wondering if she would survive the surgery.
ANSWER : A. My first question (if you could answer me back) would be how does anyone know it’s a hematoma, and not a hemangiosarcoma or a hemangioma? Hematomas usually resolve (eventually) on their own – they’re essentially bruises. So they don’t need to be surgically removed, typically. It could also be a hemangioma, which is a benign growth arising from a blood vessel. Typically no one can tell on cytology alone (that’s a needle sample taken from the mass and examined under a microscope) whether a growth like this is cancerous (hemangiosarcoma, or HSA) or benign (hemangioma, or HA). If a biopsy has been done and a diagnosis of HSA has been made, or it’s a HA and it’s causing your dog pain or discomfort, then I would agree that surgery is necessary.

As to whether she would survive the surgery, if your vet is competent in anesthesia (preoperative blood work and chest x-rays have been done to ensure that your dog is healthy otherwise, anesthetic monitoring on blood pressure, heart rate, EKG, oxygenation, etc will be done) and the mass is in a spot that is amenable to removal (i.e. There is plenty of skin in the area to close over the defect created by the excision) then I would say her chances of survival are very good. All this is assuming that the mass is subcutaneous (under the skin) and not actually inside the chest. If it’s in the chest, that’s a much more serious procedure. You can select “consult” if you want to talk about this further.

Q. I have a 10 yr old Lab border collie mix. He’s really active and acts younger than he is. Would it be safe for him to jump hurdles like agility?
ANSWER : A. It’s important to keep our older dogs active but go slow and stop early before an injury occurs. It would be important to use a joint supplement and/or fish oil to keep his joints healthy. You could do agility but go slow and don’t push him to do too much. Try your best to listen to his body language to know when he’s tired and doesn’t want to continue. I think it would be good for him to do it but not too much. It would be a good workout to keep him healthy. Make sure to have lots of water available for him when doing agility.

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Q. My cat will not eat the renal food my veterinarian recommended, can I feed a grocery store food?
ANSWER : A. Your veterinarian recommended a therapeutic kidney diet because it has ingredients that will help slow the progression of your cat’s conditions, especially phosphorus and lower protein levels. Many of the non-prescription or grocery store foods generally have high levels of phosphorus and would not be ideal for your cat.

To help your cat accept the new food It is important to do a transition. There are two reasons to do a transition:

1) Occasionally a pet will have a GI upset when switched to a new diet,

2) A pet will accept a new food better when a transition is done to allow the pet to get use to the new texture and flavor.

There is more of a chance with a hydrolyzed protein or different (high or low) fiber level food to cause a GI upset. Transition recommendation:

1) Recommend ¾ old diet – ¼ new diet

2) Do this for a few days; if no GI upset, go to the next step

3) ½ old diet – ½ new diet

4) Do this for a few days; if no GI upset, go to the next step

5) ¼ old diet – ¾ new diet

6) Do this for a few days; if no GI upset, go to the next step

7) End with 100% of the new food.

Sometimes a transition should be longer, especially for cats. Use the same recommendation, but instead of a few days, recommend doing each step for a week or more. If you cat is still not interested in the new diet you can research other non-prescription diets focusing on the labels for appropriate levels of phosphorus and protein.

Also, home cooking may be an option but make sure to provide adequate nutrients. A good website to consult is balanceit.com. This website helps you to create well balanced home cooked recipes and offers supplements to add into the diet.

Q. Dog six months has stop eating and drinking all together for five days now. Vet says not to worry. She ribs are starting to show what could be wrong?
ANSWER : A. I would be worried. Not eating or drinking… Step one is to figure out why, step two is change in food to encourage weight gain. I would recommend a good physical exam by a veterinarian, and some abdominal radiographs to rule out an obstruction. Given that it has now been 6 days, I would recommend hospitalized supportive care. IV fluids, plasma if available, and antibiotics if indicated. In regards to nutrition, high calorie food such as Hills a/d will help, but once recovered I would simply put on a high quality puppy food such as Acana, Orijen, lotus, honest kitchen etc. Human grade ingredients with less additives. Best of luck. If you would like to consult and discuss in further detail, I would be happy to help.

Q. 2 month old Bulldog. While playing gets TOO rough:gripping hand REALLY tight/growling/shaking to the point of drawing blood. Aggresive?Normal?HELP!!
ANSWER : A. For the most part, this sounds pretty normal to me. English Bulldogs can be like this. What you can do is teach him bite inhibition. He needs to know that biting gets him nothing. Each and every time he nips, even gently, you immediately yelp like a puppy would, stand up, cross your arms, and ignore your puppy. Once he is ignoring you, go back to calmly playing with him WITH A TOY. Remember to always use a toy when playing with/petting/interacting with puppies. They will be teething very soon, and they don’t understand that biting you is inappropriate, so using a toy to redirect their attention is important. He needs SOMETHING to bite, or else he will choose your hand. Give him more options.

Another thing you can do is have a toy that YOU OWN. This can be a soft braided rope toy or something of the like. Dot not allow your dog to have this toy whenever he wants. This toy disappears when you are done playing with him with it, and reappears when you want to play. Never allow him to “win” games with this toy. Eventually, the toy will hold so much meaning, when he sees it, he will be instantly interested in the toy instead of your hands.

It also helps to have two bags of toys. Bag#1 is full of chew toys/rope toys/soft toys/etc. It comes out for one week, and then disappears and out comes Bag#2. Bag#2 has the same types of toys in it. This will keep the toys feeling like “new” to your pup and make him less likely to chew on you during play!

Q. I have a Pitbull fully grown and she has ate a swiss roll. Will she get poisoned or sick?
ANSWER : A. I can’t see any poisonous ingredients within the standard swiss roll recipe. I assume she is quite a big girl, she might get a bit of gastro-intestinal upset or if the swiss roll was large and high in sugar content she might get a bit dehydrated because of the sugar component, if too rich in fat there is the risk of pancreatitis too. I would not worry too much at this stage, I would not feed her within the next 8 hours but just make sure she has got plenty of water available. If she should start to be lethargic, or more than 1-2 episodes of vomiting and diarrhoea, I would recommend a check up. If no problems seen after the 8 hirs, offer he a bland diet of plain white meat and rice, for the next 2-3 meals then gradually reintroduce her normal diet.

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Q. Approx 8 years old, had her for 4 years, last couple months has been peeing in/out of her box on furniture,blankets,etc. Never had this behavior.
ANSWER : A. Most of the time when a cat is peeing on your personal belongings such as your bed or piles of clothing/blankets the cat is telling you it is upset about something. Try to think of what could have happened that brought change to the cat’s life. Such as a new baby, new house, new pet, change in routine. New food, new liter, ect. I would try to address what was the change if possible. Make sure to keep the box clean and try adding more boxes. 1 box per cat and 1 box per house story. (2 story house 2 cats = 2-4 boxes).