Another possibility you may want to discuss with the vet is Trifexis. It takes care of fleas, hookworm, roundworm, and whipworm - all in one convenient monthly pill. Not all vets sell it, but it can be purchased online. If purchased at vet, the manufacturer (Elanco) offers a rebate. Last year, according to a local vet, the fleas were going after all dogs no matter what they were taking. The vet's office said just keep ensuring all the dogs were kept on schedule taking whatever preventative treatment, do frequent checks and brushing, and if you find fleas in home you've got to take swift and thorough action to get rid of the eggs: wash every linen/textile/soft items in hot water & detergent, clean all floors, vacuum any carpet & immediately throw away the bag outside.
Addressing comment below:
Trifexis. which I recommend, does Not control Ticks! There is a huge difference! My now retired vet cautioned me that he would never recommend tick prevention because ticks are hearty creatures so the chemicals in those prevention products are super toxic. It’s better to check the dogs coat & process specific blood tests timely if needed. However heartworm is fatal. If a dog ends up with heartworm, it will enlarge the heart until it results in fatality. If a dog has other worms or fleas, it will also have a great deal of discomfort. I contemplate, research, and make decisions for my dogs best health very seriously. BTW - He’s been on flea/worm prevention for approx 14 years & will celebrate his 16th birthday soon. So please understand, he is not being poisoned.!
I live in Florida so I have flea and tick issues. I use baths for fleas and certifect for ticks. The certifect works on the fleas as well. Read the labels of the medicines and always ask your vet. Not all medicines work for all pets.
We use a product called "food grade diatomaceous earth" all year round and especially during the summer months when our dog is apt to pick these things up from outside. They live in the grass. It works on cats and dogs and the food grade product is safe to ingest. On the carpet, on the animal WORKS!