Common Drug Combo Raises Blood Glucose

Researchers have discovered that the commonly used combination of two drugs — the antidepressant paroxetine (brand name Paxil) and the cholesterol-lowering medicine pravastatin (Pravachol) — can cause unexpected increases in blood glucose levels, even though neither medicine has this effect when taken alone. It is estimated that between 500,000 and 1 million people in the United States may be taking this drug combination.

It is not unusual for medicines to have effects when taken simultaneously with other medicines that they do not have when taken alone, but since most drugs are approved independently, it can be impossible for physicians to predict these effects. In an effort to keep track of them, the US Food and Drug Administration encourages physicians to report any unexpected side effects to their Adverse Event Reporting System (AERS).

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To identify combinations of drugs that cause altered blood glucose levels, researchers searched AERS for pairs of medicine that appeared to cause high blood glucose only in combination. They found four such pairs, and focused on the match-up of Paxil and Pravachol because it is such a commonly prescribed combination.

None of the people in the AERS taking this combination were directly reported to have high blood glucose — only symptoms of high blood glucose — so the researchers then evaluated the medical records from patients at the Stanford University School of Medicine, Vanderbilt University, and Harvard Medical School who were taking these medicines. They discovered that 135 people without diabetes who had prescriptions for both drugs had experienced an average increase in their random glucose levels of 19 mg/dl since beginning treatment and that 104 people with diabetes had experienced an average increase of 48 mg/dl since beginning both drugs.

Subsequently, the researchers investigated the effect of this combination of medicines in mice given a high-fat, high-calorie diet. After several weeks on this diet, the mice developed prediabetes (a condition in which blood glucose levels are higher than normal, but not high enough to be considered diabetes) and experienced an increase in their blood glucose levels. When the mice were then given either Paxil or Pravachol alone, their glucose levels did not increase further. When given both medicines in combination, however, their average blood glucose levels increased dramatically, from roughly 128 mg/dl to 193 mg/dl.

Senior study author Russ Altman, MD, PhD, a professor of bioengineering, genetics, and medicine at Stanford, stated that “Understanding and mitigating the effect this pair of medications has on blood sugar could allow a person with diabetes to better control his or her glucose levels, or even prevent someone who is prediabetic from crossing that threshold into full-blown diabetes.”

If you are taking this combination of drugs, do not stop taking either of them without speaking with your doctor first. You may want to discuss these findings with him, however, to determine whether there is an alternate combination of treatments that may address your health concerns without potentially impacting your blood glucose control.

For more information, read the article “Dangerous Side Effect of Common Drug Combination — Paxil and Pravachol — Discovered by Data Mining” or see the study in the journal Clinical Pharmacology & Therapeutics.

  • Judy

    Since I have been Diabetic 2002 type 2 My hair has gone 2 Hell!! With the med’s I take Junuva, Glipside!! Help!! They should do Research on that! Am Master hair stylist for years and have tried every thing on market! Also tested??? Judy

  • Char

    Interesting! I am taking Pravacol and often experience very high blood sugars, for no food intake reason. I’ll speak to my doctors about this.

  • jeff

    I was put on venlafaxine (Effexor – anitdepressant) for neuropathy and noticed an immediate drop in my glucose (inside the first 12 hrs). Had to start taking 15 less units of insulin a day because kept having lows in the first 3 days on the new drug.

    Taking –
    lantus, actos, metaformin

  • don newman`

    I’m sure these are not the only such situations. Look at Crestor and Avandia. We are not being protected from predatory pharma corps. Money is everything and the doctors are prescribing according to pharma advice. Some of the potential problemds with these new drugs far outweigh the illness being treated.

  • CARMEN

    WHAT WERE THE OTHER DRUGS? I TAKE SERTRALINE AND SIMVASTATIN. MY BLOOD GLUCOSE HAS BEEN HIGHER THAN NORMAL LATELY. I AM ALSO ON A PLATEAU IN MY WEIGHT LOSS. I WEIGHED 362 AND LOST DOWN TO 311. I AM NOW DOING WHAT I CALL THE YOYO EFFECT. WHAR CAN I DO SO THAT I CAN KEEP LOSING WEIGHT/

  • DONNA PEASE

    I AM NOT SURPRISED, I WAS GIVEN PREDNISONE IN VERY HIGH DOSES LAST FALL FOR BRONCHITIS AND SINUS
    INFECTION AND IMMEDIATELY MY MUSCLES WEAKENED TO THE STATE THAT i COULD NOT GET OUT OF A CHAIR AND COULD HARDLY WALK BY MYSELF I WAS DIAGNOSED WITH 3 BAD DISEASES AND IT TURNED OUT I HAD NO DISEASE BUT IT WAS JUST A TERRIBLE REACTION TO PREDNISONE.
    NOW I WONDER IF WAS THE OTHER DRUGS I TAKE SUCH AS PAXIL THAT CAUSED MY REACTION.

  • Keen

    Have been diabetic (type 1)since 1880. About mid 1980’s my hair started to fall out in droves all over the pillow. Don’t think it was the medication as I was only on Metformin. I now take Glyburide & Januvia as well as Insulin. Now 21 years later I worry about going completely bald as my scalp is very visible.

  • Helen

    I am taking janumet and I loose a lot of hair every day

  • mrbasicshark

    Myself, I would caution anyone taking Januvia to becareful. I know it is a pretty popular drug. However here is what I found on it, and I suggest you research it as well, just dont take my word on it. Ok, here goes….Januvia in a class of medications called dipeptidyl peptidase-4 (DPP-4) inhibitors…In other words they stop the action of the DPP-4 enzyme in the body…Ok, so What does the DPP-4 emzyme do? (1)plays a major role in glucose metabolism (2) responsible for the degradation of incretins such as GLP-1 (3)it appears to work as a suppressor in the development of cancer and tumours. (4) is useful as a marker for various cancers, with its levels either on the cell surface or in the serum increased in some neoplasms and decreased in others.
    Ok , I will stop there. Just read 3&4, the DPP-4 enzyme plays a role in suppressing cancer. So why inhibit or stop such an emzyme from working?

    Draw your own conclusion, but I think they are to many other diabetic drugs available to use this one and take away 1 line of cancer defense. Just reseaarch yourself and be aware.

    This in no way constiutues medical advise. Continue to follow your doctor’s orders, and direct any questions or concerns to the proper healthcare professional.