I personally use homeopathic remedies for most insect stings/bites and find them to be the most effective at truly curing the sting, rather than merely suppressing the symptom (what we see). My girl just got stung by a bee last week and was very unhappy about it. It took me quite a while to find it but I eventually did and removed the stinger - it was very red. I iced it as should be done for all red, or inflammed bites and then gave her the appropriate remedy, in this case Rhus Tox matched her symptoms and characteristic s. She was holding her leg up and wouldn't stand on it when we started....wit hin a couple of hours the redness was gone and she was walking around fine. Apis is another common remedy as well and these are found in your local healthfood store.
If you are not familiar with homeopathy, you should consider taking a closer look as it has been invaluable in addressing common issues with my dogs.
If you aren't comfortable with homeopathy then there are several natural remedies that help easy discomfort of bites and dilute the sting. Wash the bite thoroughly to remove any toxins, ice it to provide comfort and decrease swelling, and apply Lavendar oil for instance to poisonous bites like snake bited, every 20 minutes until medical help is found. Tea Tree oil is also effective as an antiseptic.
All of these things treat the issue at hand - the bite instead of introducing a drug into the system.
Good luck!