If I have this wrong, please tell me/us.
After the Japan problem, I bought the dosage recommended for two people and it is stored. I think when one “dose” is used, it means that round of doses making up what one should take. The amounts I have are two “doses” meaning the number of pills required to be the course of the treatment. They are in a blister pack with instructions. One blister pack per person.
I got them for two people but I can't take them as they would kill me since iodine is like a poison to me. It's on my medical records never to give or use iodine on me. Living in Texas, I hope radiation doesn't come here. I have the pills for two people and that would be my relatives because I can't take it. I know for sure the pills would kill me so I would have to take a chance the radiation wouldn't.
These tabs have limited usefulness. I have a couple of packs to provide about 3 days of protection for my family.
IMO of more use are methods to prevent exposure. Sheet plastic, the simple face masks, and long sleeve clothes. If you can keep from breathing in contaminated material and keep from getting it on you it will help reduce exposure.
The only other real thing you can do is get out of the contaminated area.
As long as you are 25 miles away from the blast, you can survive with appropriate sheilding. IIRC, That could be a couple of feet of concrete all around you or 5 inches of steel, 3 feet of water, for example. Like maybe a bath room or closet?
You would need to stock about 2 weeks of supplies in the shelter with you, IIRC. After the first week, you can come out for a few minutes to dump your waste if you have to.