frontline and advantix contain pyrethrum. which is a derivative of the chrysanthemum flower. it's a very poisonous seed (however it gets extracted the name changes, pyrethrin, permethrin etc.) that has a high level of acute toxicity in cold blooded animals (insects, frogs, etc.) ... however, in MOST mammals the affect is not as dramatic, but it's still poison. it WILL kill a cat
, but dogs (and most mammals) can deal with the compounds more appropriatley.
it's on you shoulders at the end of the day to know exactly what you feed your pet (and yourselves!!!) i can almost guarantee that this is why your dog vomited. it took their system some adjusting to deal with.
i would recommend incorporating garlic and 1 tbsp of apple cidar vinegar to water and/or food every day.
i wash with cal ben coconut shampoo (the same stuff i use) but i add rosemary and tea tree oil to his mixture. rosemary will kill whatever insect and being accompanied with the tea tree oil it will cure any rash or skin irritation your dog may be having (watch out for open wounds, scabs. it will burn like the dickens.) spray apple cidar vinegar (1 part acv 5 parts water) let that sit for 5 minutes, then rinse. then rub him down with coconut oil to restore integrity to the coat/skin and choke to death any remaining flea/tick.
the higher alkaline (7.0) your dogs pH is... the more prone they are to attracting bugs. be careful though, you wouldn't want the dog to start having ulcers for a trade-off for no fleas/ticks. and apple cidar vinegar will drop your dogs pH. you must monitor it before incorporating it in their diet.
if those don't work, then you gotta do what you gotta do for your buddy. this problem sounded terrible, and i would have done the same thing. now that they're healthy, try the organic route! it's much more work, but it's a lot more bonding.