Dogs can take zoloft but before giving a medication such as this you should speak to your vet as there are side effects and this medicine may react to other medications. Some dogs may have allergies to the drug and you don't want to cause harm to the dog. An allergic reaction can be serious where it affects the breathing. Having this happen on a Sunday when the vets are closed would be risky to say the least. Here is more on this and side effects.