Hi Nancy,
I am sorry your kitty is so ill. There is absolutely nothing that you can give her at home that will humanely euthanize her, so please DO NOT administer anything. The drugs you have available for your own use are not going to ensure a smooth or quick death for your kitty, and she deserves to go peacefully and with dignity. Various human drugs will cause symptoms that range from seizures to kidney or liver failure, and these are not pleasant or quick ways to die.
If you want a humane euthanasia, you will have to call a vet and either take her in or see if someone will come to you. You can contact your local humane society or SPCA and inquire about low cost services that they may provide. I urge you to contact a vet, it is sure to be very uncomfortable for your kitty if she lingers and suffers until she dies of natural causes at home. Please let me know if I can be of further assistance. If this has been helpful, please hit the green accept button. I am very sorry about your kitty.
Emergency Critical Care Nurse
16+ years of veterinary experience