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What Is The Cause Of Increased Blood Sugar When On Carvedilol?

Posted on Tue, 4 Mar 2014

Question: i started carvedilol 6.25 mg tablets two months ago. My average heart rate has dropped to 60 from 90, but my blood sugar has incresded to 300 from 120. Should I drop this drug or find one without this impact on glucose metabolism. My other drugs include meformin for glucose control and fosinopril and amlodiphin for blood pressure control My cardiologist recommended this drug, but I don't think he expected this adverse effec on blood sugar control.

Answered by Dr. Rakesh Karanwal (31 minutes later)

Brief Answer: Carvedilol does NOT affect blood sugar levels Detailed Answer: Hi there, Thanks for your query. Firstly, you have not mentioned the time (in relation to meals- fasting or 2 hours after a meal) at which blood sugar was tested. It may be noted that blood sugar varies with time of the day. Also, blood sugar is dependent on the carbohydrate content in the diet. Further, Carvedilol has NO role in the sugar metabolism. It is a very useful drug. SO, PLEASE DO NOT STOP CARVEDILOL. It is therefore possible that a certain dose of metformin- which had earlier controlled blood sugar level- is no longer effective and therefore needs increase in the dose. Please check your fasting and 2 hours post-breakfast blood sugar. Based on the reports, your treating doctor will titrate the dose/frequency of anti-diabetic drug(s). Hope I have addressed to your concerns to your complete satisfaction and you find my response helpful and informative. I will be happy to answer further queries, if any. Fond regards and have a nice day, Col (Dr.) Rakesh Karanwal

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Rakesh Karanwal (31 minutes later)

Your answer was almost worthless.I am sorry I asked. My web research indicates this drug can have a substantive impact on blood glucose levels. I test my blood sugar in the morning prior to any food inytake. I find it incredulous that you would suggest increasing dose of metformin to counteract the impact of this drug. I will review your response with n my primary doctor and cardiologist but Ithink the best course of action is to stop this drug and go back to the drug regiment I have been following for four years with good results.

Answered by Dr. Rakesh Karanwal (33 minutes later)

Brief Answer: Clinical trial shows no adverse effect of carvedil Detailed Answer: Though this forum is not meant to quote articles or the outcome of clinical trials conducted scientifically in support of our opinion, I would nevertheless draw your attention to the abstract of a scientific clinical study :- " Hypertension With Type 2 Diabetes Mellitus In a double-blind study (GEMINI), Carvedilol, added to an ACE inhibitor or angiotensin receptor blocker, was evaluated in a population with mild-to-moderate hypertension and well controlled type 2 diabetes mellitus. The mean HbA1c at baseline was 7.2%. Carvedilol was titrated to a mean dose of 17.5 mg twice daily and maintained for 5 months. Carvedilol had no adverse effect on glycemic control, based on HbA1c measurements.." My opinion was based on the very low dose (6.25mg/day) of Carvedilol. The above-quoted trial showed that even a high dose of 35mg/day of Carvedilol had no adverse effect on glycemic control! You are most welcome to discuss this aspect with your primary doctor / Cardiologist and draw your own conclusions. I accept your criticism of my opinion with great humility. Good Bye and Take Care

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Rakesh Karanwal (16 hours later)

I would direct you to the following web sites before you ever again state that this drug has no effect on blood glucose levels. It certainly has for me increasing to 300 from a well regulated 120 without the drug. 1. WWW.WWWW.WW 2. WWW.WWWW.WW There are several more under a Bing search of carvedilol and blood sugar. I guess the final question is whether it is better to have a heart rate of 90 or a blood glucose level of 300. I think the former, but perhaps you disagree.

Answered by Dr. Rakesh Karanwal (5 hours later)

Brief Answer: Coreg+Metformin combination LOWERS sugar levels Detailed Answer: The point of contention has been identified. My opinion was strictly with reference to YOUR case and based on the provided information that your blood sugar- which was 120 while on Metformin- had increased to 300 following addition of Carvedilol. There is a drug interaction between Carvedilol and Metformin (belonging to Biguanide group of anti-diabetic drugs). Use of both drugs together, LOWERS THE BLOOD SUGAR LEVEL, as evident from the following websites:- (a) WWW.WWWW.WW (b) WWW.WWWW.WW On the other hand, Carvedilol INCREASES blood sugar levels in diabetics who are on Insulin or Insulin-stimulating drugs (Sulfonylurea group of anti-diabetic drugs, such as, glimepiride, glibenclamide and gliclazide), by reducing the effect of insulin. NOTE MAY BE MADE that the information given on the net is primarily for the laymen and, commonly, omits finer details. This leads to confusion in the public's mind. Hence, in your case, there are two possibilities:- (a) In Type II Diabetes, there is a progressive destruction of Insulin-producing cells with consequent progressive reduction in Insulin production --> hyperglycemia. There is therefore, a progressive increase in the requirement of anti-diabetic drug(s). It may have been a sheer coincidence that blood sugar was already on the rise at the time of adding Carvedilol; or, (b) As a result of Somogi Phenomenon/Dawn Phenomenon ("Rebound hyperglycemia") :- Addition of Carvedilol to Metformin caused a unduly low blood sugar, which stimulated the counter-regulatory mechanism, thereby leading to a higher than usual fasting blood sugar. The description of the two phenomena are there on the internet. IN YOUR CASE, THE FIRST POSSIBILITY IS MORE LIKELY. As per my experience, 6.25mg of Carvedilol is too low a dose to significantly lower the blood sugar level and stimulate counter-regulatory mechanism to come into play. Read the effects of Coreg (as per the website referred by you) which says "If you are taking Coreg and blood sugar levels drop too low or go too high....". Carvedilol can both : INCREASE or LOWER the blood sugar level in diabetics. Incidentally, having treated more than 100,000 cases of diabetes in my 35 years of clinical experience, the dose/frequency of anti-diabetic drugs rarely stay static for more than 18-24 months. Lastly, I am almost of your age, with a vast clinical experience. Display of basic decency, tolerance, patience and net-etiquette from a mature gentleman like you, would be very much appreciated in future. You are welcome to verify my opinion from your PR/Cardiologist/internet.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Rakesh Karanwal (1 hour later)

Thank you for the time you have spent and the referenced web sites. Ihave reviewed your answer and the web sites and find that the combination of metformin and carvedilol may in fact be responsibe for the changes in my heart rate and blood glucose levels. Stopping the carvedilol may in fact reverse those changes. Increasing the metformin to couter act the increase in blood glucose levels may also work, but I would generally avoid taking a drug to counteract the effects of another drug. The final question posed was whether it is better to have a heart rate of 90 or a blood glucose level of 300. I do not believe you have answered that final question. Thank you again for your attention to this matter. I have forwarded your responses to both my cardiologist and regular doctor who will plot a change to my drug regiment considerering your advise.

Answered by Dr. Rakesh Karanwal (21 minutes later)

Brief Answer: Glycemic control should be the first priority Detailed Answer: None of the two issues is a lesser evil. Since the risk of developing heart disease increases manifold in patients with Hypertension and uncontrolled diabetes, first priority should be to achieve glycemic control to ideal level and a BP of 120/80. At the same time, heart rate too needs to tackled simultaneously. If I were your treating Cardiologist/Endocrinologist, I would have continued with Carvedilol and instead, carried out blood sugar profile (fasting and 2 hours each after breakfast, lunch and dinner) and would have modified Anti-diabetic therapy, based on the profile reports. Lastly, even at the risk of repetition, I would like to emphasize that 6.25mg of Carvedilol is too small a dose to significantly alter blood sugar levels.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Rakesh Karanwal (34 minutes later)

FYI the prescription doses are as follows: metformin 500mg tablet 1/day fosinopril 40 mg 1/day amlodipine 10mg 1/day simvistatin 40mg 1/day carvedilol 6,25 mg 4/day my nonprescription drugs include aspirin 325mg, ginkobiloba 120mg, Dr. Sinatra omega Q 100 plus, Dr. Sinatra heart healthy multivitamin 2/day, and medix select glucose reduce .2/day. This regiment has kept my blood pressure below 120/80 and my blood glucose below 130. The actual intake of carvedilol added to this regiment is 4 times what you assumed if that makes any difference. No question here, just supplemental information.

Answered by Dr. Rakesh Karanwal (12 hours later)

Brief Answer: I fully agree with your Cardiologist's decision Detailed Answer: I have taken note of the treatment regimen and FULLY AGREE with your Cardiologist's decision regarding Carvedilol's dose. Carvedilol's beneficial effects FAR OUTWEIGH its side effects. It reduces the workload on the heart by reducing the heart rate, as well as, by dilating the blood vessels and thereby sends less blood load on the heart. It therefore improves the prognosis by protecting the heart. The ideal goal is : * meticulous glycemic control (by re-adjusting the dose of Metformin); * Ideal Blood pressure control; * protection of the heart; * prevention/delaying of the onset of diabetic complications (kidneys' impairment, heart disease, involvement of the nerves particularly of the legs/feet). Lastly, I personally am of the opinion that aspirin is NOT required at this stage. Or, its dose should reduced to 75mg/day. IT IS JUST MY PERSONAL OPINION. But it is your legal and fundamental right to either heed or ignore my advice.

Note: For further queries related to coronary artery disease and prevention, click here.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar