Side effects of graoefruit + atenolol

Grapefruit juice tends to inhibit a specific group of liver enzymes responsible for metabolism of drugs, and the drugs stay in the body longer to cause possible side effects. Only drugs that rely on metabolism by the group of enzymes inhibited by grapefruit juice will be affected by grapefruit juice.

Atenolol relies primarily on kidney excretion instead of liver metabolism. Its removal from the body is less dependent of liver enzymes and therefore, it is okay to take grapefruit juice while taking atenolol.