Potency drug can lower blood sugar in long-term in type 2 diabetes

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A pilot study conducted at the University of Gothenburg found that people with type 2 diabetes who were treated with high-dose tadalafil strongly improved their long-term blood sugar levels.

The drug is a medication used to treat erectile dysfunction. However, a larger study is needed to confirm these results over a longer period.

What is tadalafil?

Tadalafil is one of the active pharmaceutical substances known as PDE5 inhibitors, a group that also includes Viagra. PDE5 inhibitors are used to treat impotence or erectile dysfunction (ED).

Unlike the other three PDE5 inhibitors that are approved in Sweden, tadalafil is long-acting and can be prescribed as a daily dose.

The Study

The study included 18 participants, 12 men, and 6 postmenopausal women.

They were randomly assigned to receive either a high daily dose (20 mg) of tadalafil or a placebo for six weeks.

After an eight-week break, they were then given the other option for six weeks. The study participants were monitored for side effects since tadalafil has a number of known side effects.


The primary aim was to investigate whether tadalafil might enhance the patients’ insulin sensitivity. In this respect, there was no discernible difference compared with the placebo.

However, tadalafil caused a clear improvement in metabolic control based on measurements of hemoglobin A1c (HbA1c) in blood samples.

On average, the level of HbA1c fell by 2.50 mmol/mol.

That’s a very distinct improvement in long-term sugar levels, which is on par with what we’ve seen with new drug candidates that are now the fourth treatment option for type 2 diabetes.

Hemoglobin A1c (HbA1c) is precisely monitored in blood samples from patients who are undergoing treatment for type 2 diabetes.

The higher the HbA1c value, the greater the risk of complications, including microvascular damage to the eyes, kidneys, and nerves.


Tadalafil has the potential to supplement the treatment currently given for type 2 diabetes, especially for men who also have ED. More than 70% of men with obesity and type 2 diabetes develop ED.

However, the results from the pilot study need to be repeated in a larger study where more patients are treated for a longer period of time, which the University of Gothenburg research group is now considering.

The current primary treatment for type 2 diabetes combines lifestyle changes with the drug metformin. In the past 10 to 20 years, several other new drugs have also been developed.

Tadalafil increases blood flow in skeletal muscle, heart, and adipose tissue.

This present study also shows increased blood flow and a favorable effect in the liver, where an established marker of fatty liver decreased during the drug treatment compared with the placebo.

In addition, the researchers saw an increase in glucose uptake with the tadalafil treatment compared with the placebo.

It is important to note that self-medication with PDE5 inhibitors must never take place because, at worst, it can be life-threatening in combination with certain other drugs.

These medicines are available on prescription only and must always be prescribed by the attending physician.

If you care about diabetes, please read studies that MIND diet may reduce risk of vision loss disease, and Vitamin D could benefit people with diabetic neuropathic pain.

For more information about health, please see recent studies that blueberries strongly benefit people with metabolic syndrome, and results showing eggs in a plant-based diet may benefit people with type 2 diabetes.

The study was published in eClinicalMedicine.

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