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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

People’s Pharmacy: Don’t worry about vitamin D and metformin

Vitamin D tablets are displayed in New York in 2016. One study concluded that taking metformin doesn’t lead to a vitamin D deficiency.  (Mark Lennihan/Associated Press)
By Joe Graedon, M.S.,</p><p>and Teresa Graedon, Ph.D. King Features Syndicate

Q. Is it true that metformin depletes vitamin D levels? Should patients taking metformin for Type 2 diabetes also take a vitamin D supplement?

A. A randomized controlled trial that lasted more than a year answered this question (Diabetes, Obesity & Metabolism, August 2018). After 16 months, participants taking metformin did not have significantly different blood levels of vitamin D (25 hydroxyvitamin D) compared with those on placebo. The authors conclude: “Our results show that metformin doesn’t lead to vitamin D deficiency.”

On the other hand, people taking metformin may not have adequate vitamin B12 (World Journal of Diabetes, July 15). Patients should request periodic testing and if deficient, they should take a supplement under medical supervision.

Q. My doctor prescribed Humira for ankylosing spondylitis, and I took it for several years. While it made a huge improvement in my life, I noticed that I was much more susceptible to colds and minor infections. If anyone at work had the sniffles, I could almost guarantee I would have those symptoms in a couple of days.

Through diet changes, supplements, exercise and use of other medications, I have weaned off biologics like Humira. It took several years for my body to return to normal. I now rarely get colds. Other AS patients report similar experiences. My conclusion is that biologics are important tools in the toolkit but are not perfect solutions.

A. Ankylosing spondylitis is an autoimmune arthritislike condition that primarily affects the spine. Immune-modulating drugs such as adalimumab (Humira) may also be useful for other autoimmune conditions, including rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, Crohn’s disease, ulcerative colitis and plaque psoriasis.

Other medications in the class include abatacept (Orencia), anakinra (Kineret), certolizumab (Cimzia), etanercept (Enbrel), golimumab (Simponi), guselkumab (Tremfya), infliximab (Remicade), natalizumab (Tysabri), rituximab (Rituxan), tocilizumab (Actemra) and ustekinumab (Stelara).

Such drugs are pricey and often advertised on television. Like you, many people state that these immune modulators dramatically improve the quality of life. But they also have some serious drawbacks. Your experience with infections is not unusual.

One commercial, for example, states that “Humira can lower your ability to fight infections. Serious and sometimes fatal infections including tuberculosis and cancers including lymphoma have happened.”

The Food and Drug Administration requires a black box warning regarding serious contagious diseases including TB and fungal infections, as well as those caused by bacteria, viruses and other pathogens.

Q. Can any of the following meds keep me awake at night: metformin, losartan, meloxicam or amphetamine salts?

A. The most obvious culprit is the amphetamine. Such drugs are considered stimulants and are often prescribed to treat attention-deficit/hyperactivity disorder. Some familiar brand names include Adderall, Dexedrine, Mydayis and Vyvanse. Other side effects of such medications beyond sleeping difficulties may include loss of appetite, rapid pulse, anxiety, irritability, dry mouth and digestive distress.

You may find our eGuide to Getting a Good Night’s Sleep helpful. It lists many common medications that can cause insomnia and offers a variety of approaches to overcome sleeplessness. You can find this online resource under the Health eGuides tab at

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email them via their website