Those who prefer green tea as their morning beverage have just been warned that the drug can interact with a beta blocker blood pressure medicine called nadolol (Corgard). Ten people were given either three cups of green tea or water daily for two weeks. Then they were given a single dose of nadolol.
Those who had been drinking green tea had about 76 percent less nadolol in their bloodstreams later. Urinary levels were 80 percent lower. The researchers suggest that people who must take nadolol should probably stay away from green tea. Those in the green tea group got markedly less blood pressure lowering effect from the nadolol.
It has been known for years that green tea could dramatically lower levels of the chemotherapy drug bortezomib (Velcade). Perhaps it would be helpful for scientists to investigate possible interactions of green tea with other medications.
There are many other foods and beverages that can affect medications. Here is a link to our free Guide to Drug & Food Interactions.