New research suggests antibiotics do not increase the risk of chronic fatigue symptoms, and there are no links between antibiotic use and fatigue symptoms in people with chronic fatigue.
The study was published online in the Journal of Clinical Endocrinology & Metabolism.
“This is the first study to show a direct association between antibiotic usage and fatigue,” says lead author Anastasia Zhelezny, PhD, an associate professor in the Department of Medicine at Johns Hopkins University.
“But it does not prove a causal link.”
Chronic fatigue syndrome is a condition in which people experience symptoms of fatigue, joint and muscle aches, shortness of breath, short and fast movements, muscle weakness, and poor concentration.
The condition is estimated to affect between 10 and 25 percent of people worldwide, according to the World Health Organization.
Symptoms include fatigue, low energy, and depression.
The majority of people with the condition have mild or moderate symptoms.
Antibiotics are commonly prescribed for the condition, and a recent meta-analysis of clinical trials found the use of antibiotics was associated with a significant reduction in the number of reported cases of the condition.
The meta-analyses included more than 2,000 studies involving more than 20,000 participants, but researchers have yet to determine how often antibiotics are prescribed and whether people who are prescribed antibiotics are more likely to have fatigue symptoms.
Zhezzny and her colleagues decided to test whether antibiotic use was associated, rather than whether it was associated solely with fatigue.
They recruited participants who had been taking antibiotics for the last two years and were between the ages of 18 and 45.
The participants completed a battery of measures, including fatigue, and had a history of chronic disease.
“It’s not uncommon for people with fatigue to take medications that have a positive effect, such as acetaminophen or fluoxetine, to manage fatigue,” Zhezny says.
“However, when they are prescribed a drug that does not have a beneficial effect, the drug may also cause fatigue.”
The researchers then compared the number and types of antibiotics prescribed to those that were not prescribed.
“If the antibiotics were not administered to people who were on antibiotics, it was very unlikely that they would have an effect,” Zhalezny says, “so we looked for factors that might increase the chance of a positive association between antibiotics and fatigue.”
They found that, as expected, people who used more antibiotics were more likely than people who did not use antibiotics to report fatigue.
“We found no association between the number or types of medications and fatigue, suggesting that antibiotics are not associated with fatigue at all,” Zhozny adds.
“People who take more antibiotics are also more likely, on average, to be on antibiotics for longer periods of time.”
People with chronic illnesses who take antibiotics are typically treated with antibiotics.
However, the use and administration of antibiotics can cause severe side effects.
“Antibiotics have an extremely high potential to cause adverse side effects, so people should always consult their doctor before taking them for chronic illness,” Zhu says.
The authors also note that antibiotic use may not be a good predictor of whether people with a chronic illness will develop fatigue symptoms themselves.
The researchers also looked at people with no history of fatigue.
Those with no symptoms of chronic illness were also more than four times more likely as those with chronic illness to report that they were prescribed antibiotics.
“Although this study did not show a causal relationship between antibiotic prescribing and fatigue or other side effects,” Zhuzny says “it does not show that antibiotics have no effect on fatigue.”
Zhezazny and colleagues suggest that the best way to prevent fatigue is to get your immune system to fight off infections and other infections.
For this study, the researchers also compared the effectiveness of antibiotics to placebo, and they found that the treatment was significantly more effective than the placebo.
“Given the lack of a direct relationship between antibiotics, and fatigue and other side symptoms, the effectiveness could be attributed to the immune system’s response to the drug,” Zhanzny concludes.