There are quite a number of commonly prescribed and over-the-counter medications that need to be avoided when taking lithium. Or if they must be taken, extra care must be used in monitoring lithium levels.
Some drugs cause lithium levels to increase, and a person can become toxic on his regular dose of lithium. Some other medications can actually increase the rate at which the kidneys filter the blood and thereby cause a decrease in lithium levels.
The following two tables include many of the more common medications to watch out for. There are more, so it’s always a good idea when starting a new medication or over-the-counter pill to ask your pharmacist or prescriber to run a drug-interaction profile.