How Does Phenobarbital Affect My Dog’s Back Legs

In this research you will know the answer to the query “How Does Phenobarbital Affect My Dog’s Back Legs“.

We wrote this research for all the dog owners out there whose dogs suffer from seizures.

A specific medication Phenobarbital is being used to manage their seizures.

The focus of the research is specifically on the effects that this medication can have on your dogs back legs.

It remains to be seen whether this is a short-term blip or a long-term symptom.

Beyond this this post can be viewed as Phenobarbital 101 since I cover other side effects and the most important things to consider when your dog starts taking Phenobarbital.

First lets take a look at the simple stuff.

What is Phenobarbital?

Essentially phenobarbital is a barbiturate used to treat seizures in dogs. It can also be used to sedate other animals such as cats ferrets and even horses. It is usually sold under the brand names Luminal Sodium Solfoton and Federal. Alternative generic names for phenobarbital include phenobarbitone phenobarbital phenmalum phenobarbital phenyl ethyl barbituric acid and phenyl ethyl malonylurea (pardon the long names). 

In fact Phenobarbital has been used as an anti-seizure medication for over 100 years (primarily by humans) since 1912. To date it is also one of the most affordable medications to combat seizures. 

Vets now prescribe it to dogs as prescription medicine so be sure that your tail-wagging pal follows the veterinarians instructions. In the United States phenobarbital is classified as off-label which means that the FDA has not officially approved it for use as a sedative. Most medications are typically prescribed off-label so as long as you follow your veterinarians instructions you should be fine. 

How effective is Phenobarbital in treating seizures?

Phenobarbital relieves seizures by simply hampering and stabilizing neuron activity levels in your dogs brain. In this way GABA levels are elevated (a neurotransmitter that calms nerves) while glutamate levels are lowered (a neurotransmitter that stimulates nerve cells). There is no other medication that can compete with Phenobarbital when it comes to its effectiveness and affordability. 

How long does it take a dog to adjust to Phenobarbital?

You need to consider factors such as your dogs weight as well as the severity and frequency of his seizures. Phenobarbital functions best when given on a regular basis according to the prescription instructions from your veterinarian. You should give them the medication for the entire duration indicated and not suddenly stop it as it should be reduced slowly and gradually. If the medication does not take effect immediately you may need to continue giving it for a couple of weeks. Nevertheless after a few doses you should be able to see gradual improvements. 

What is the correct dosage for Phenobarbital?

Different dogs respond to and absorb the medication at different rates. Thus the dosage is dependent on a few factors such as the weight and severity of your dogs seizures. Once your vet has taken all these factors into account he or she will prescribe a specific dosage which is usually between 1 and 2 mg of Phenobarbitol per pound of body weight. By every we mean to try not to miss a single dose and by every we mean every 12 hours or twice a day.

Depending on your pets preference phenobarbitol is available as a tablet capsule paste liquid solution or chewable. Phenobarbitol can be administered pre- or post-meal. If your dog vomits when Phenobarbitol is given before a meal then administer the medication after meals as a future intake. 

Considering Phenobarbital may not be so great for your pets liver your vet may require regular blood testing every 2 to 6 months to monitor liver function and prevent complications. 

It is not advisable to give your dog two doses at the same time if you accidentally miss a dose. Rather than skipping a missed dose continue with the regularly scheduled dose.  

What issues does Phenobarbital cause in the back and why?

Taking anti-seizure medications can cause ataxia a condition in which your canines body loses its balance and lacks the ability to coordinate voluntary movements particularly the hind legs. This can be observed when your pet falls wobbles trips lacks coordination or collapses. 

Phenobarbital causes ataxia in dogs when given to them in the early stages or when the dosage is increased since the drug causes increased ataxia. Do not panic though! The ataxia should wear off over time as your dogs body adjusts to the regular intake of medication. 

All of you responsible and caring dog owners should take extra care of them during the early stages of the medication especially when they climb stairs or walk on slippery surfaces. If your home has slippery surfaces such as tiled or hardwood floors you might try adding some rugs to give your pet some traction. 

As your furry companion tries to regain control please be patient and bear the strength to support them at this time. 

We highly recommend getting professional medical advice from your local vet for further diagnosis and possible treatment if your dog shows very little to no improvement from ataxia. 

What are some other side effects of Phenobarbital?

Despite being a long-time anti-seizure medication phenobarbital does have some side effects on canines. You should be aware of the following side effects: 

  • Even for humans anxiety is not pretty 
  • Agitation
  • An increased appetite thirst and urination
  • Incoordination (may indicate a dose too high) 
  • Reduced red blood cells (do not worry this is a less common side effect) 
  • Liver dysfunction (super rare but watch out for symptoms such as yellowing of the skin vomiting anorexia and skin ulcers)

Phenobarbital should not be used if your dog has underlying medical conditions such as kidney inflammation/infection allergies severe breathing issues or severe liver diseases. Please consult your veterinarian if your dog is anemic dehydrated pregnant or lactating so you can safely administer the medication. 

Is there an alternative to Phenobarbital?

To date phenobarbitol has been the most commonly used and effective medication for treating seizures in dogs despite its not-so-favorable side effects. Should phenobarbitol run out or if you simply want a second or third option we’re here to help? Below are some alternatives to Phenobarbitol you might want to consider: 

Potassium bromide

In some dogs either on its own or in combination with Phenobarbitol this medication is effective. Like Phenobarbitol it also causes incoordination weakness and in some cases skin problems (yikes!). Other distinct side effects include nausea or vomiting. 

This medication may not be suitable for dogs with kidney issues because they may not be able to excrete the drug and may accumulate toxins in their blood. 


Diazepam a medication known to relieve anxiety can also help some breeds of furry dogs manage seizures. The most common side effects include drowsiness disorientation and incoordination (just like Phenobarbitol). 

What are the other major causes of back leg weakness in dogs?

You can expect your tail-wagging pal to experience back and hind leg weakness if he or she is taking anti-seizure medication. It is therefore crucial that you and your veterinarian carefully assess these symptoms in order to get the correct treatment for your dog. 

Hind leg weakness may be caused by age (due to degeneration of joints and muscles over the dogs lifetime). These are some specific causes of back leg weakness in dogs: 

  • Myelopathy degenerative 
  • Injury (strengthened the muscles and tissues as a result of trauma) 
  • Intervertebral disc disease 
  • Diabetes (not pleasant to have)  
  • Poisoning from toxic substances 

The symptoms of this symptom are more complicated than they seem. Hence you should always make sure you know the exact cause before deciding which medications to take. 

You should take your dog to the veterinarian as soon as possible if they show signs of back leg weakness such as incoordination tripping and wobbling. Please let your veterinarian know every detail including current medications changes in appetite and behavior as well as any medical history of back leg weakness. 

How should you care for a dog with weak back legs?

There are a variety of causes for weak back legs such as old age disease or arthritis but caring for dogs with weak back legs is the best way to aid them in their recovery. Integrating a healthy meal plan for your pet is one of the best ways to care for them and prevent future hind leg weakness. 

Dogs with weak hind legs should have a diet rich in omega 3 and omega 6 fatty acids calcium and vitamin B1 to strengthen their bones and muscles. It is always a good idea to consult with your veterinarian regarding the best diet to feed your dog especially if your dog is suffering from underlying health conditions such as diabetes. 

Regular and proper exercise is another way to lose weight. Taking your puppy out for a walk to the park at a very young age can help shape an active lifestyle for them and benefit them in their senior years by ensuring they have strong hind legs as opposed to dogs who do not exercise much. 

If you want to read more about dog health tips read here: Dog Health Tips and Tricks.

How Does Phenobarbital Affect My Dog’s Back Legs (Watch Video)

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