tonda,
every medication, from penicillan to lithium, is atually a poison and will afect the boy one waay or another. each person is diffeent in how we metabolize or excreat meds, so the effects of a particular rx on one person will be different in how it effects another person.
not everyone gains waight on bp meds. gaining weight is a side effect that not every individual gets.
every drug, vitamin, mineral, protien drink, and food consumed has inherent interactions. for example, oil based vitamins interact negatively to water nabased vitamins. some say you should never take them together.
lithium and some other nood stabelizing drugs play havoc with the thyroid, which is why you should have your thyroid checked every 6 mos to a yr. taking thyroid supplements, such as the ones you have mentioned, should be taken at least an hour before taking lithium or two hours after taking it. my phamacist and dr agreed that this woud give me the best chance of both drugs working and causing the least interaction.
hope this helps.
warren