• Medical Author:
    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Causes of Fatigue Slideshow Pictures

Can drug therapy be matched to the "body clock?"

The time of day also can affect the way our bodies respond to medical therapy, especially drug therapy. Investigators working in a special area of chronobiology, called chronotherapeutics or chronotherapy, are studying these effects. Their goal is to come up with new medications, or improve existing ones, that make the most of what we know about how the body clock works.

Already there is evidence that taking medication "by the clock" helps the drugs work better and reduces their side effects. Currently, some doctors are prescribing nighttime administration of medication for patients with ulcer disease or asthma (which worsen at night), rheumatoid arthritis (which worsens in the early morning hours), and high cholesterol levels (most of the body's cholesterol production occurs at night). For patients with osteoarthritis, which worsens in the afternoon and evening, some doctors are prescribing midday medication.

Drugs that may be given "by the clock" include corticosteroids, nonsteroidal antiinflammatory drugs (NSAIDs), antihistamines, theophyllines, and anticancer drugs.

These lists are growing as chronobiology, chronotherapy, and the diagnostic and treatment methods derived from them are slowly accepted by the medical community. However, the broad acceptance of chronobiology in medicine is expected to take (excuse the expression) some time.

Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine


The right time? Chronopharmacology - a new science. Nursing RSA Verpleging. 1992;7:23-27. Pharmacology.

Smolensky MH, D'Alonzo GE. Medical chronobiology: concepts and applications. Am Rev Respir Dis.1993;147:S2-S 19.

Time of day medicine dose is taken may boost its efficacy, cut toxicity. JAMA. 1996;275:1 143-1 144. Medical News & Perspectives.

American Heart Association; "Know the Facts, Get the Stats 2007."

Centers for Disease Control, National Center for Health Statistics; "Allergies/Hay Fever."

Centers for Disease Control, National Center for Health Statistics; "Asthma."

Medically Reviewed by a Doctor on 6/18/2015

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