After kittens first vet visit, they hate each other, How long does this last?

My 2 most lovable sister kittens are now 31/2 months old. I just took them to the vet for the first time (my first time to a vet too). They got rabbies vaccine, Feline Distemper-something- Combo shot, and Aids/Leukemia shot. They were also both spayed and treated for earmites and had to stay over night. I asked the vet if it was too much for them at one time, she said no, they will be okay.
Well the problem is that now they are at home and do not recognize each other. They hiss and fight with each other and sometimes me too. They are really loopy. They have to be locked in separate rooms basically, so they don't hurt each other while in recovery from their surgery. I spoke with the vet yesterday and she said this normally happens for the first few hours when they are away from the vet because they smell like the kennel. But it has now been 3 days, she says to just wait and let her know if it last any longer... Well how long could this last, what's wrong w/ them? I can't bathe them yet

Cats do rely very heavily on their sense of smell. They use it to identify each other and can find unfamiliar scents very threatening.

I had a similar experience when one of my indoor cats sneaked outside and hid in the engine space of a parked car. As soon as I brought him inside,our female cat began attacking him. I had to keep them separated for almost a week before the female calmed down. Intermingling their scents will help your kittens get on again. On a daily basis, try swapping over their litter trays and bedding, or take a soft cloth, wipe it over one kitten and then wipe the cloth on the other kitten. Alternatively, take an unwashed item of your clothing and stroke that over each kitten so that they both have a scent they know and find comforting. You can also swap over the rooms that you keep them in. That way they can investigate the other's scent and become familiar with it again. When they can be together in the same room without hissing or fighting, reward them with food treats, so that they associate each other with nice things again.

Feliway is a great product, but because it works by building up a feeling of well-being in cats, it can take up to 3 weeks before you begin to see the benefits.

Hope this helps.

go get the Feliway plug in. its a phermone that makes cats relax and cover eachothers smell. it will work like a charm

Feliway is great I use it all the time both the plug and the spray. You could also sit on the floor with the pair of them and encorage them to play with you and together. My cats are like yours and it can take them up to a week to settle down but trust me it will pass. Cats are creatures of habit and do not lke change of any kind whetehr it is a trip to the vet or being in a cattery and it takes time for them to settle back into their surroundings.

our kittens are brother and sister.they hated each other for a while about a week.male was done first and she hated him, hissing and stuff.the females seem to be worse than the males.he didnt mind her when she came back from the vets!dont worry the'll be back to their cute playfull selfs soon enough!the'll naturally get over it.give them a couple of weeks and see what happens then try something like sprays.there expensive and generally dont work.