Taking ZzzQuil With Lipitor (Atorvastatin)

There is no interaction between ZzzQuil (diphenhydramine) and Lipitor (atorvastatin).


Is it safe to take ZzzQuil, a nighttime sleep-aid, while I am taking Atorvastatin before bedtime?

Asked by grftnlrd On Aug 30, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Sep 04, 2018

There are no drug interactions between Zzzquil (diphenhydramine) and atorvastatin (Lipitor). They can be taken at the same time with no concerns. Read more about both diphenhydramine and atorvastatin below.


Information About Diphenhydramine

Diphenhydramine (Benadryl) is a first-generation antihistamine. Antihistamines are widely used for self-care of allergy symptoms including runny nose, watery eyes, sneezing, and itching of the nose, throat, or eyes. Benadryl may also be used for symptoms of the common cold, allergic reactions, occasional insomnia, and more.

Because Benadryl is a first-generation antihistamine, it is more likely to cause sedation and drowsiness. Other first-generation antihistamines include Dramamine (dimenhydrinate), Chlor-Trimeton (chlorpheniramine), Tavist (clemastine), and Phenergan (promethazine), among others.

These medications cross the blood-brain barrier and have CNS effects like drowsiness and dizziness. First generation antihistamines can also cause urinary retention, GI upset, and blurry vision. The first generation antihistamines are also listed as medications to avoid in elderly adults by the Beers Criteria due to the increased risk of confusion, dry mouth, and drowsiness.

Second generation antihistamines include Claritin (loratadine), Cetirizine (Zyrtec), and Allegra (fexofenadine) and are much less sedating. These antihistamines are generally only used for treatment of allergy symptoms, whereas Benadryl can be used for a variety of reasons including allergies, insect bites, poison ivy, sleep, and motion sickness.


Information About Atorvastatin

Lipitor (atorvastatin) is a statin medication, otherwise known as an HMG-CoA reductase inhibitor. Lipitor gradually decreases the amount of total cholesterol, LDL cholesterol (known as “bad” cholesterol), and triglycerides. Atorvastatin can reduce LDL levels by up to 45-60%. Atorvastatin 40-80 mg is considered a high intensity statin per the American College of Cardiology and American Heart Association.

Lipitor is metabolized by several processes, especially CYP3A4, P-glycoprotein, and OATP1B1. The most significant drug interactions with Lipitor come with medications that reduce or increase the activity of CYP3A4. 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. Inhibitors can increase the effect of Lipitor, which may lead to side effects like muscle pain and a severe condition known as rhabdomyolysis. Examples of CYP3A4 inhibitors include diltiazem, digoxin, grapefruit, and many HIV medications. Diphenhydramine does not inhibit CYP3A4.  

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%. Avoid grapefruit juice to avoid risk of side effects. 

About the Pharmacist

Dr. Kevin Davis Pharm.D

Dr. Kevin Davis is a licensed pharmacist with experience in retail and hospital pharmacy. He graduated from the University of Florida with a Doctor of Pharmacy degree in 2015 and a Master of Healthcare Administration degree from Adventist University in 2017. He is also a Board Certified Pharmacotherapy Specialist since 2016.

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