Impact of Antibiotics on Fatigue: Do They Make You Tired?

Does Antibiotics Cause Tiredness? Key Insights

Research has shown that antibiotics can cause a variety of side effects, including gastrointestinal disturbances, allergic reactions, and, notably, fatigue. While fatigue is not universally accepted as a direct side effect of all antibiotics, certain classes of these drugs have been linked to lethargy and exhaustion.

A systematic review of the effects of antibiotics on energy levels highlights several factors contributing to fatigue, including the impact of antibiotics on gut microbiota, the resulting changes in metabolism, and the body’s immune response to both the infection and the medication (Kurian, 2025). Additionally, individual differences, such as age, pre-existing health conditions, and the type of antibiotic used, can influence the severity and experience of fatigue.

Effects of Antibiotics on Energy Levels

The relationship between antibiotics and fatigue can be complex. Initially, antibiotics target the infection causing fatigue, but the aftermath can sometimes lead to increased tiredness due to several factors:

Gut Microbiota Disruption: Antibiotics can disrupt the balance of gut bacteria. The gut microbiota is essential for various functions, including nutrient absorption and the synthesis of vitamins like B12, which are crucial for energy metabolism. A study indicated that antibiotic-induced dysbiosis might lead to increased fatigue, as nutrient absorption is compromised (Ma et al., 2025).
Immune Response: The immune system’s response to both the infection and antibiotics can lead to fatigue. The body expends energy fighting off an infection, and while antibiotics help, the recovery phase can still be taxing on the body (Zhang et al., 2024).
Direct Side Effects: Some antibiotics, such as tetracyclines and fluoroquinolones, have been associated with neurological side effects, including fatigue and malaise. These side effects can be exacerbated by the individual’s overall health and concurrent medications (Hutchings et al., 2019).

Understanding the Connection Between Antibiotics and Fatigue

The connection between antibiotics and fatigue is multifaceted. It involves physiological and psychological components:

Physiological Factors: Fatigue can arise from the disruption of normal physiological processes. For instance, antibiotics can alter the body’s metabolic pathways and immune responses, contributing to feelings of tiredness and lethargy.
Psychological Factors: The stress of illness and the anxiety associated with taking medication can also contribute to fatigue. Patients may feel overwhelmed by their condition, which can perpetuate a cycle of fatigue (Pan et al., 2021).
Interactions with Other Medications: Many patients on antibiotics may also be taking other medications, leading to potential drug interactions that can amplify feelings of fatigue. It’s crucial for healthcare providers to review all medications a patient is taking to minimize this risk (Medoro et al., 2023).

How Different Types of Antibiotics Impact Your Body

Understanding the specific types of antibiotics and their potential side effects can provide insights into why fatigue may occur:

Beta-lactams (e.g., penicillin, amoxicillin): Generally well-tolerated, but gastrointestinal side effects can lead to discomfort and fatigue.
Tetracyclines (e.g., doxycycline): Associated with side effects like photosensitivity and gastrointestinal disturbances, which can contribute to a general feeling of malaise.
Fluoroquinolones (e.g., ciprofloxacin): Known to cause fatigue, dizziness, and even neurological effects in some patients, particularly in the elderly or those with renal impairments (Gandhi et al., 2023).
Macrolides (e.g., azithromycin): These can also lead to gastrointestinal upset, which may indirectly cause fatigue through poor nutrient absorption.
Aminoglycosides (e.g., gentamicin): More severe side effects can include nephrotoxicity and ototoxicity, which affect overall health and energy levels.

Managing Fatigue While Taking Antibiotics

Effective management strategies can help mitigate fatigue experienced during antibiotic treatment:

Stay Hydrated: Ensuring adequate fluid intake can help maintain energy levels and support overall health.
Balanced Nutrition: Eating a well-balanced diet rich in vitamins and minerals can counteract some of the nutritional deficiencies caused by antibiotics (Li et al., 2023).
Rest and Recovery: Prioritizing rest is vital. The body needs time to recover from both the infection and the effects of antibiotics.
Monitor Symptoms: Keeping track of fatigue levels and other side effects can help healthcare providers adjust treatment plans as necessary.
Consult Healthcare Providers: Open communication with healthcare providers about fatigue and other side effects can lead to tailored interventions and medication adjustments.

When to Consult a Healthcare Professional About Fatigue

Patients should be proactive about their health, especially when dealing with fatigue during antibiotic treatment. Consulting a healthcare professional is advisable when:

Fatigue is Severe or Prolonged: If fatigue persists beyond the expected recovery period or significantly impacts daily life, a medical evaluation is necessary.
New Symptoms Arise: The emergence of new symptoms, such as unexplained weight loss, persistent fever, or other concerning signs, warrants immediate attention.
Other Health Conditions Exist: Individuals with pre-existing health conditions should consult their healthcare provider sooner, as they may be more susceptible to the side effects of antibiotics.

FAQ

Can all antibiotics cause fatigue?
Not all antibiotics cause fatigue, but certain classes, particularly fluoroquinolones and tetracyclines, are more likely to lead to tiredness as a side effect.

How long can fatigue last after taking antibiotics?
Fatigue can last for several days to weeks after completing a course of antibiotics, depending on the individual’s health, the type of antibiotic, and the underlying infection.

What should I do if I experience fatigue while on antibiotics?
It’s important to communicate with your healthcare provider about your symptoms. They can help determine if the fatigue is related to the antibiotic or the infection.

Are there any specific antibiotics that are known to cause less fatigue?
Beta-lactams (like penicillin) are generally well-tolerated and are less likely to cause fatigue compared to other classes of antibiotics.

How can I improve my energy levels while taking antibiotics?
Staying hydrated, eating a balanced diet, resting, and managing stress can help improve energy levels during antibiotic treatment.

References

Kurian, R. (2025). Prodrugs in Oncology: Bioactivation and Impact on Therapeutic Efficacy and Toxicity. International Journal of Molecular Sciences. https://doi.org/10.3390/ijms26030988
Zhang, M., et al. (2024). Systemic lupus erythematosus: Current treatment and future directions. Current Opinion in Rheumatology
Hutchings, M.I., Truman, A.W., & Wilkinson, B. (2019). Antibiotics: Past, Present and Future. Current Opinion in Microbiology. https://doi.org/10.1016/j.mib.2019.10.008
Pan, Y., et al. (2021). The impact of COVID-19 on mental health and coping strategies: A longitudinal study. Journal of Psychological Research
Medoro, A., et al. (2023). Assessing the impact of antibiotic therapy on gut microbiota and patient outcomes. Journal of Clinical Microbiology
Li, Z., et al. (2023). Nutritional management during antibiotic therapy: A review. Clinical Nutrition. https://doi.org/10.1016/j.clnu.2023.01.005
Gandhi, T.K., et al. (2023). How can artificial intelligence decrease cognitive and work burden for front line practitioners? JAMIA Open