I am often asked, “When is the best time of day to take my dex: morning, mid-day, or bedtime”?  Let’s explore the answer from the aspect of normal human physiology.

Understanding the Physiology of Dexamethasone 

Cortisol is an adrenocorticoid produced each day by the adrenal gland.  It is essential to life, is a major factor in controlling our reaction to stress, and significantly affects our moods, energy, digestion, immune system, and emotions. 

The adrenal gland, like many others in the body, is controlled by the pituitary “master gland” which constantly monitors body hormone levels, regulates glandular activity, and controls adrenal hormone production.  Other endocrine organs, such as the thyroid, are also regulated by the pituitary gland. 

Our “master gland” produces TSH (thyroid stimulating hormone) to stimulate the thyroid gland to greater function when it senses there isn’t enough circulating thyroid hormone passing by. 

Similarly, the pituitary monitors adrenal glands (located above the kidneys). Cortisol serum levels are diurnal, meaning they naturally fluctuate by the time of the day.  Endocrinologists take two serum cortisol levels when checking adrenal gland function, one at 8:00 AM and one at 4:00 PM. 

Typically, the morning level is much higher as the adrenal gland responds to ACTH, a regulatory hormone that stimulates the adrenal gland to produce cortisol.

Dexamethasone Timing in Multiple Myeloma Patients 

Why does all this matter? It matters because dexamethasone is chemically similar to cortisol.    

If we take a high dose of dexamethasone at bedtime, there is still a significant blood level of dex in the morning. When the pituitary discovers there is plenty of steroid in the blood passing by it decreases ACTH production. This tells the adrenal gland not to produce any cortisol in the morning following an evening dex binge.

To further help understanding consider what happens when cortisone (dex) is taken four days in a row, the way it often used to be prescribed for myeloma. For four mornings, the adrenal glands are told by the pituitary to stand down. They do nothing. Now assume the myeloma patient adjusts their dexamethasone schedule and abruptly stops daily cortisone. 

The pituitary tells the adrenal glands to get to work, but they have become lazy, unresponsive, and do nothing.  The pituitary begins screaming by producing high levels of adrenal-stimulating hormones (ACTH), but the adrenal glands respond with “yeah, whatever”. In time, they slowly respond and again produce daily cortisol, the way they are supposed to do every morning.

In the meantime, however, the patient has no physiologic cortisol and, therefore no stimulus to increase metabolic activity when the rest of the body is begging for help. 

Another great example of this is surgery. Anesthesiologists always ask their patients if they have been taking any steroids. If they have, the doctor expects that there may be a blood pressure problem or a wake-up problem because that patient’s adrenal glands have become lazy and unresponsive. The worst of these possibilities leads to an “Adrenal Crisis”, which can translate into a true medical emergency.

The Bottom Line: When to Take Your Dexamethasone? 

The bottom line, therefore, is that it is much more physiologic to take all corticosteroids (dex, prednisone, prednisolone, Solu-Medrol, etc.) in the morning when the body expects there to be an elevated steroid level. 

You will get much less adrenal gland suppression if you take steroids (dexamethasone) in the morning than if you take them at night.

It is much wiser to take all steroids in the morning hours, not at night.  You will probably do OK if you take them at night, but your pituitary and adrenal glands will follow a regular physiologic routine if you give that steroid dose in the morning.

While dexamethasone might bring about a cleaner house or a shopping spree, it can also bring about severe mood swings and unwanted rapid weight gain. If you are experiencing side effects from the dexamethasone that significantly lower your quality of life (or the quality of life of those around you), please talk to your doctor about a dose reduction. No physician or treating medical team wants you or your family to be so negatively affected by treatment. 

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Dexamethasone Resources

If you want to learn more about dexamethasone, consider one of the following resources. 

• HealthTree University (Free Myeloma Education): All About Dexamethasone and other Corticosteroids 
• Jenny Ahlstrom Orginal Dexamethasone Song
• Steroids 101: Darn that Dex Webinar with Myeloma Specialist Dr. Banerjee
• Recently Published Dexamethasone Research: Seniors Enjoy Life with Less Dex (ASH 2022) Article 
• Myeloma 101: Dexamethasone and Blood Sugar Article 
• HealthTree Medication Information Pages: Dexamethasone 

Remember, if you need help interpreting your myeloma labs, you can look here: Understanding My Myeloma Labs or call our Patient Experience Team at +1 800 709 1113.