Can You Have Grapefruit If You Take Lipitor (Atorvastatin)?
In our latest question and answer, the pharmacist discusses whether or not Lipitor (atorvastatin) interacts with grapefruit and related extracts.
Can you take multiple blends of extracts with atorvastatin? I was told cannot eat grapefruit with this prescription. The blends of extracts are citrus seed, evodia fruit, areca seed, blue citrus peel, fennel seed, viadimirie root, and lindera root.
Many of these citrus extracts listed have at least some evidence that they can inhibit important enzymes responsible for drug metabolism. Citrus seed extract, also known as grapefruit seed extract, has been shown to inhibit CYP3A4 which is important in breaking down atorvastatin. This can lead to the same adverse effects that are worrisome with grapefruit—muscle pain and rhabdomyolysis.
Grapefruit And Lipitor
CYP3A4 is the most common enzyme responsible for breaking down medications. Many drug interactions are due to inhibition or induction of CYP3A4 and other CYP enzymes. Inhibiting the enzyme allows for drugs that require CYP metabolism to stay in the body longer at a higher concentration. Inducing the enzyme would cause rapid metabolism of the drug and would therefore diminish its effect.
Per the Lipitor package insert, one study showed that drinking one glass of grapefruit juice (8 ounces) with atorvastatin resulted in an increased drug concentration of 37%. Drinking excessive amounts of grapefruit (approximately 1 L/day) increased drug concentrations 250%.
Herbal supplements, such as the extracts listed, are not FDA approved and do not have the robust data needed to assess effectiveness and safety in the general population. Because of this, it is difficult to determine the risk involved when taking with other medications.
As stated previously, many of the extracts listed do have some evidence of inhibition of CYP enzymes. These include citrus seed (grapefruit seed extract), evodia fruit, and fennel seed. The other extract blends may also interact, however, limited data exists.
One of the grapefruit seed extract studies showed a significant interaction with warfarin that caused a bleed in just three days. This also was shown to interact with CYP3A4. After further testing, the culprit of the interaction was found to be benzethonium chloride that was contained in each of the grapefruit seed extracts tested. This study highlights the risk of taking supplements with limited quality controls.
To summarize, taking these extracts could cause an increased concentration of atorvastatin, but the true risk is difficult to determine. The risk is likely dependent on the potency of each extract and the overall CYP3A4 inhibition. Higher concentrations of atorvastatin could increase the likelihood of side effects including muscle aches and rhabdomyolysis.