What are the risks of treatments?

Risks are very minimal. Sometimes I've seen some GI upset, but usually, if you give the flea and tick medication with food, that prevents that.

It depends on the product you are using. For example, topical products and flea and tick collars, especially the cheap ones, can cause intense skin reactions. There's always a risk even with better quality products because every patient is different and will react differently. There will always be a risk of skin irritation or reaction. Another thing that most people are aware of is the neurologic side effects. That's how these products kill fleas and ticks, so the concern is whether it will cause neurologic side effects in a pet. We tend to see these problems with cheaper, over-the-counter products, but there will still be a risk even with the best products.

The biggest concern is the neurologic side effects. Have a discussion with your veterinarian to decide on the best product for your pet, taking into consideration their history, breed, and physical exam findings. One thing that would lead me to decide on a different product than I would typically choose is if your pet has a history of seizures, which could increase their risk of certain side effects. That being said, I have seen dogs with a history of seizures staying on these products without it having any effect on their seizures. So it won't cause your dog to have seizures, but those are the clinical aspects to consider when making a decision.