Tramadol Raises Risk of Low Blood Sugar

By Pat Anson, PNN Editor

Patients who take the opioid tramadol are at greater risk for developing hypoglycemia – a condition caused by very low blood sugar -- than those taking other pain medications, according to researchers at the University of California San Diego.

Prescriptions for tramadol – a synthetic opioid sold under the brand names Ultram and ConZip – have been increasing because it is perceived as a “safer” opioid with less rick of addiction. Tramadol is currently ranked among the top five prescribed opioids in the United States.

As tramadol use has grown, so have documented cases of adverse effects such as dizziness, nausea, headaches and constipation — all common side effects of opioids.

The link to hypoglycemia was discovered by accident when researchers at UCSD’s Skaggs School of Pharmacy and Pharmaceutical Sciences analyzed more than 12 million reports from the FDA’s Adverse Event Reporting System from January 2004 to March 2019.


“The impetus was the recent dramatic surge in tramadol popularity and prescriptions,” said Tigran Makunts, PharmD, first author of the study published in Scientific Reports. “We wanted to have an objective data-driven look at its adverse effects and bumped into a dangerous, unlisted and unexpected hypoglycemia.”

The researchers compared adverse events involving tramadol to those linked to other widely prescribed opioids and non-opioid medications, such serotonin and norepinephrine reuptake inhibitors (Cymbalta, Effexor XR) and NMDA receptors (ketamine and memantine).

Only tramadol produced a significant risk of developing hypoglycemia. There was a 10-fold greater risk of hypoglycemia using tramadol than virtually every other opioid except methadone, which is typically used to treat addiction.

Hypoglycemia is often related to the treatment of diabetes, but can also occur in persons without diabetes. Left untreated, hypoglycemia can lead to serious complications, such as neurocognitive dysfunction, vision loss, greater risk of falls and loss of quality of life.

“The takeaway message is to warn physicians about the likelihood of low blood sugar, in particular if the patient is predisposed to diabetes,” said senior author Ruben Abagyan, PhD, a professor of pharmacy at UCSD.

“It may be beneficial to monitor glucose levels when initiating tramadol or methadone in both diabetic and non-diabetic patients. Alternative opioids or non-opioid pain medications may be safer to use with patients at risk of hypoglycemia or any complications associated with hypoglycemia.”

Tramadol was classified in 2014 by the DEA as a Schedule IV controlled substance, a category that means it has a low potential for abuse. A recent study, however, by Mayo Clinic researchers found that patients who took tramadol for post-surgical pain have a slightly higher risk of prolonged use than those taking oxycodone or other short acting opioids.

In 2017, the FDA banned the use of tramadol in children under the age of 12, citing a handful of cases where children died or had serious breathing problems after using the drug.