I have to be honest and admit that I don't always follow my own doctor's directions. I'll forget to take a dose, or get near the end of a prescription and decide that I probably don't need to continue taking them. And I know better!!!! "Bad, Dr. Bern! Take your meds!" As someone in the medical profession, I know all of the reasons why I need to follow my doctor's recommendations.
So why is it so important? And why bring that up in a mostly-veterinary blog? The exact same problem happens with pets and their owners. A pet will start to feel better or symptoms will improve and the owner will stop giving medications. Or they miss several doses and get off schedule. Several studies have shown that pet owners' compliance with the vet's directions is far lower than we veterinarians believe. Such noncompliance can actually have negative consequences. Let me go over a couple of examples.
Antibiotics normally need to be given for at least 10-14 days, and often longer (especially with severe skin or urinary infections). You should never stop antibiotics as soon as the symptoms go away because the bacteria may not be gone. There needs to be a certain level of infection before you notice an issue clinically. An infection may still be present, but the bacterial numbers have been reduced to the point of no longer seeing an obvious problem. We call these sub-clinical infections. However, in these cases the bacteria are still there! When you stop antibiotics, any remaining bacteria can then start to grow again and the problem can come back as bad as ever. Dermatologists recommend continuing antibiotics for two weeks past complete resolution of symptoms! Another danger is that any remaining bacteria were not killed immediately and so may have some degree of natural resistance to medications. Allowing them to live and reproduce could be selecting for a resistant strain that then won't respond well to antibiotics.
Another example...demodex mites are not uncommon in puppies and there are various treatments available (oral ivermectin, amitraz dips). These mites are pretty sturdy and it normally takes several months of continual treatment to cure the pet. As the pet is improving any hair loss starts to resolve and grow back. I have had clients stop treament once this happens, and in many cases they end up back in my clinic because the problem came back. They didn't follow my recommendations and stopped treatment too soon, before all of the mites were dead.
Doctors don't prescribe medications for a given length of time based on how much money they want to make. There are well established protocols based on strong data for how long it takes to eradicate a given infection or cure a problem. The length of time will vary based on the severity of disease, the tissues involved, the type of bacteria, and other similar factors. So some infections may be gone in 10 days, but others may take 2-3 months. This extends beyond infections to other diseases as well. The frequency of administration (once daily, twice daily, etc.) is also important and varies between medications based on their method of action. Not giving it at proper intervals (such as giving a twice daily medication only once daily) can prolong a disease or result in a lack of a cure.
The bottom line is that you need to competely follow your vet's directions for your pet. Finish the medications as they are directed!
And yes, I'm going to finish my own.