If your pet is on medication long term then I’m sure you’ve had the conversation about bloodwork with your pet’s Veterinarian. But why? Why do Veterinarians always want to monitor a pet’s medication with some type of bloodwork? Is it just a way for Veterinarians to make more money, or is there, as they say, a method to their madness?
Well let’s break this down. Medications, as people know, can have side effects. Anyone that has seen those commercials on television have heard the long list of side effects they ramble off at the end. Side effects can vary, not just from medication to medications but many times pet to pet as well. They can be mild (like diarrhea or vomiting) or severe (like bleeding, seizures or death). Bloodwork can help us monitor a medications negative effects on a pet’s body.
Bloodwork also helps us monitor a medications positive effects on a pet’s body. Most medications have a very specific therapeutic window in which they work. Too much medication in a pet’s system and those negative side effects are more likely to occur. Too little medication and it will no longer benefit the pet effectively.
Medications, when first started, can take a while before its benefits can be seen. Why you ask? This is because each medication has what is called a half-life. The half-life of a medication is the amount of time a drug is in the body before half of it is gone. The medication then continues to decrease by half until it if effectively gone. For example. If a medications half-life is 4 hours and you are giving 10mg, in 4 hours there would only be 5mg left, in 8 hours there would be 2.5 mg left and so on. This effect can happen the opposite way as well. As you give a medication you are slowly increasing the mount in a pet’s system until it reaches a beneficial level.
So why is this important? The half-life of a medication is important because it is used to determine how much medication to give, the dose, and how often to give it. Essentially tailoring the medication to your pet’s specific needs. So how does bloodwork tie in? Once a medication’s dose is determined, bloodwork is used to evaluate its long term effects by making sure that:
- Medications are not causing side effects
- Medication levels are therapeutic and helping our pets
- Medications are not interacting or reacting with other medications that may possibly being given.
Early testing, when a medication is first started can be frequent until the dose (the amount given) and dosing intervals (how often you have to give it) reach a Steady State Level (a constant and repeatable level of effectiveness), then generally less frequently for long term monitoring.