I'm not sure this is what you are looking for, but two brands of oral anti-tick/flea medicine for dogs are:
- Capstar Flea Killer - contains Nitenpyram
- Comfortis - contains Spinosad
Nitenpyram on Wikipedia:
Nitenpyram is an insecticide used in agriculture and veterinary medicine to kill external parasites of pets. It is a neonicotinoid, a neurotoxin that blocks neural messages and binds particularly tightly in the central nervous system of insects, causing rapid death.
It has been used orally in dogs, cats and some wildlife species for over 10 years. After ingestion, it begins killing adult fleas within 10 to 30 minutes and continues to kill fleas for 4 to 6 hours. The effects of nitenpyram last approximately 24–48 hours. Nitenpyram is safe to use on puppies and kittens as young as four weeks old if they weigh at least 2 pounds (0.91 kg). Panting and excitement, as well as other symptoms, have been noted in cats and dogs within 2 hours of administration. In heavily infested animals, it can cause extreme itching as the fleas die. There is no antidote for Nitenpyram poisoning.
Nitenpyram does not kill insect eggs and has no long-term activity. Thus, it is not effective as a long-term flea preventative. It is used to kill adult fleas quickly on an infested animal, and combined with a longer-term flea preventative like fipronil or lufenuron to prevent reinfestation.
Spinosad on Wikipedia
Spinosad has been used around the world for the control of a variety of insect pests, including Lepidoptera, Diptera, Thysanoptera, Coleoptera, Orthoptera, and Hymenoptera, and many others. It was first registered as a pesticide in the United States for use on crops in 1997. Its labeled use rate is set at 1 ppm (1 mg a.i./kg of grain) and its maximum residue limit (MRL) or tolerance is set at 1.5 ppm. Spinosad’s widespread commercial launch was deferred, awaiting final MRL or tolerance approvals in a few remaining grain-importing countries. It is considered a natural product, thus is approved for use in organic agriculture by numerous nations. Two other uses for spinosad are for pets and humans. Spinosad has recently been used in oral preparations to treat C. felis, the cat flea, in canines and felines; the optimal dose set for canines is reported to be 30 mg/kg.
Trade names include Comfortis and Trifexis (which also includes milbemycin oxime) (both brands treat adult fleas on pets; the latter also prevents heartworm disease), and Natroba (for human head lice). It is commonly used to kill thrips.
I'm going to make a bit of a personal statement here, I think. As you read both of the above descriptions, you might notice that the medicine used in both of the above medications is designed really for the immediate killing of fleas and ticks, in the short term. Wanting to make your pet's remaining years more comfortable and less medicated is a great ideal, but neither of these products are going to be long lasting enough to act as a preventative.
Really, your choices need to be limited (for a preventative solution) to topical oils and/or collars.