Your pet is in hospital, and the vet has recommended that they need to have a drip (intravenous fluids) to rehydrate them. This sounds like a great idea. So why is that simple bag of fluid a prescription medicine? After all, it’s just some salt water, right? Well, not quite. 

Here are five reasons why bags of fluid are prescription medicines and why (in most cases) they need to be administered by your veterinary team.

1. They are given directly into the blood system

Firstly, the way fluids are given to your pet is important. Fluids are usually administered via an intravenous catheter (or cannula) directly into your pet’s blood system. This is most commonly via a vein on their foreleg, but other sites can be used too. Any substance that enters the blood system needs to be sterile. This ensures the liquid is scrupulously clean and free from bugs and bacteria. It stands to reason, then, that any products used this way should undergo the same rigorous testing, manufacturing process and handling protocols as other medications. As a result, fluids should also be stored correctly and discarded when the product expires. Avoiding outdated products is crucial, as bacteria entering your pet’s blood could cause a life-threatening infection.

Prescription medications can only be dispensed by the vet or another approved person. Therefore, the person giving the fluids is supervised in what, how and how much is given. Fluid bags may be sent home with clients for wound flushing or to be given under the skin in chronic kidney patients. However, intravenous fluids should always be administered in a veterinary clinic as this is a technical procedure with the risk of significant harm if performed unsafely.

2. Not all fluids are the same

It’s true! There are different types of fluid made up of various electrolytes and molecules. Most fluids are manufactured to reflect the chemical balance in the blood. But some are specially designed to change that balance slightly. Your vet will know which fluid product is best for each patient and what medications can be added safely to what fluid type. For example, most dehydrated patients will require Hartmann’s fluids (Lactated Ringer’s solution), whereas a patient with liver failure would most likely benefit from saline. The type of fluid you select can affect the patient’s blood pH, which can determine whether they get better or not. This is crucial for patients with metabolic problems – for example, kidney disease or those having a diabetic crisis.

3. The body’s fluid system is a delicate balancing act

Your pet’s kidneys are amazing! And, for the most part, they do a great job of keeping hold of what they need in the blood system and getting rid of what they don’t. However, if your pet is unwell and dehydrated or their kidneys don’t function properly, this intricate system can go very wrong. Your vet will most likely do blood tests, a clinical examination and other diagnostic tests (possibly blood pressure checks and ultrasound) to determine how the fluid imbalance has occurred. These tests will help them decide which fluid and at what rate can be given safely to your pet. 

4. Fluids can save your pet’s life in an emergency 

Pets can become critically ill from all sorts of fluid imbalances: dehydration from vomiting and diarrhoea, kidney disease; hormone diseases that make them pee more; bleeding due to trauma or internally from a tumour; salt toxicity from swimming in the sea; and water toxicity from over-drinking – to name but a few! 

Your vet will need to give your pet the correct type of fluids at the right speed and over a suitable time. A bleeding patient might need immediate fluids to improve their blood pressure but might need a blood transfusion shortly afterwards. In contrast, a patient experiencing a diabetic crisis might need an intricate plan with multiple fluid types containing glucose, insulin and potassium solutions. A diabetic pet will require frequent blood tests to check that their blood levels are improving, and the fluid plan will need to be altered every few hours to reflect these results. In patients that have experienced a head injury, giving a more concentrated saline solution into the blood can draw fluid away from the brain and prevent dangerous brain swelling. Still, this fluid could be unsafe to use in another patient with a different condition.

5. Too much fluid can be harmful

As you can see, correctly using the best fluid can be life-saving, but using fluids incorrectly could harm your pet. Giving too much fluid too quickly could overload your pet’s blood system and cause fluid to leak out into their lungs. If this happens, your pet might experience breathing difficulties and heart problems, which could be very serious. This is why it is so important that your veterinary team monitors your pet whilst they are on a drip. The speed of administration and the amount of fluid a patient needs can be a complicated decision that requires your vet’s expertise. Giving fluid too quickly can be risky, but too slowly can prevent your pet from getting better, especially if they are critically ill.

Fluids are fantastic if used correctly!

Fluids are probably the most widely used, life-saving product available to vets. When used correctly, they are our greatest tool in getting many pets better. But they need to be manufactured carefully and stored safely so we can rely on them to treat our most sick patients. It is also super-important that whoever is giving the fluids knows what they are doing. Placing an intravenous catheter is an intricate skill which could lead to a severe blood infection if performed incorrectly. Your veterinary team are expert at prescribing and giving fluids to your pet, and, with fluids being a prescription medicine, your pet will always be in safe hands.

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