10/10/2025
Routine Lab Results Often Appear Normal When You’re Living with Antibiotic Adverse Effects
Part 1 of 2
If you are living with the systemic adverse effects that can be caused by a prescription of one of the drugs in the fluoroquinolone (see link) class of antibiotics, standard tests can come back “normal”. You're not alone with your frustration and you're not imagining these adverse effects!
Fluoroquinolone toxicity, or parts of it, can be deemed an invisible illness because much can be caused by biochemical and cellular dysfunction. As a result, blood tests may appear normal even when serious adverse effects are present. This disconnect can lead to patients being dismissed or misdiagnosed, not because the damage isn’t real, but because the tools used to detect it weren’t designed to look that deep.
🔍 Standard tests miss issues with:
• Mitochondria (your cells' energy factories)
• Oxidative stress balance (ROS, glutathione)
• Ion channels and nerve signaling
• Intracellular magnesium & calcium transport
• Possible drug accumulation in circulation due to genetic issue with drug clearance and/or reduced kidney function
➜ Here's why that happens:
1. Blood Tests Reflect Circulation, Not Cellular Processes
Routine panels measure what circulates in the blood, not what occurs inside the cell. Fluoroquinolones impact mitochondrial DNA (mtDNA), oxidative phosphorylation*, ion channels*, and redox* balance at the cellular level; processes not visible in standard blood work.
2. Mitochondrial Dysfunction Isn’t Detected by Standard Labs
Exposure to fluoroquinolones can lead to dysfunction of the mitochondrial respiratory chain, especially in complexes I and IV and cause abnormal mtDNA replication or segregation in mammalian cells.
3. Oxidative Stress and ROS Damage Are Invisible in Standard Panels
Fluoroquinolones generate reactive oxygen species, reduce glutathione, and promote lipid peroxidation. Such oxidative stress requires specialized markers like 8-hydroxy-2′-deoxyguanosine (8-OHdG) and/or F₂-isoprostane with creatine ratio to be documented.
4. Ion-Channel and Neurological Disruptions Are Overlooked
Fluoroquinolones act as antagonists at the GABA-A receptor and affect NMDA-related signaling. Because they chelate magnesium and calcium, they can alter neurochemical activity and increase neuronal excitability - symptomatic but invisible without targeted testing.
5. Tissue Accumulation Isn’t Measured in Serum Levels
Fluoroquinolones reach high concentrations in bone and cartilage - tissues rich in collagen. Redistribution from bone is slow, and the persistence of symptoms does not necessarily reflect measurable drug levels.
No single test confirms fluoroquinolone-related dysfunction; clinicians often look for a pattern across multiple complementary tests (see disclaimer below):
✳️MitoSwab™ – A cheek-swab test that measures Complex I and IV enzyme activity, reflecting mitochondrial function though not considered gold standard test.
✳️Nutreval FMV – Comprehensive panel assessing nutrients, mitochondria, oxidative stress, and more. (Organic acid test is included)
✳️8 OHdG – A marker of oxidative stress to DNA.
✳️F₂ isoprostane/with creatinine ratio – Marker that gauge’s lipid peroxidation and overall oxidative stress
✳️Lactate/Pyruvate Ratio – Reflects mitochondrial respiratory chain function and energy breakdown issues.
✳️RBC or Ionized Magnesium – These forms better reflect intracellular magnesium levels than standard serum magnesium, though interpretation must consider clinical context.
✳️Coenzyme Q10 (CoQ10) Levels – Often depleted in mitochondrial dysfunction and after oxidative drug exposures.
✳️Muscle or Nerve Biopsy – Rarely done, but may show mitochondrial myopathy, denervation, or axonal injury.
✳️Neurotransmitter Panels (urine or plasma) – These may indicate peripheral imbalances of GABA, glutamate, or dopamine; however, they do not necessarily reflect brain activity and should only be interpreted as functional indicators alongside metabolic markers.
✅Doctors Who Commonly Order These Tests
To access tests like MitoSwab or neurotransmitter panels, patients typically need to see a doctor in functional, integrative, osteopath (DO), or naturopathic (ND). While these types of providers frequently operate outside insurance networks, they commonly use specialty labs like Genova, Great Plains, or Doctors Data. In contrast, conventional doctors rarely order these tests but may offer muscle biopsies or lactate/pyruvate panels in specific cases. The NutrEval FMV can be ordered by the patient directly without a doctor.
♦️The Way Forward♦️
A better understanding of fluoroquinolone toxicity, broader insurance coverage for expanded laboratory testing, and acknowledgment of mitochondrial dysfunction are urgently needed. Since October 1, 2025, the new ICD-10-CM code T36.AX officially recognizes adverse effects of fluoroquinolone antibiotics (ICD-10-CM FY2026, U.S. Centers for Medicare & Medicaid Services).
Visit our “Find Help” page below for further information.
➤ Part 2 will explain why imaging scans can also fail to show the metabolic and structural changes seen in those affected.
Glossary:
*Oxidative phosphorylation ➥ this is how your cells make most of their usable energy. Inside mitochondria, oxygen helps pull electrons along a tiny conveyor belt, and the energy from that flow is used to pack energy into ATP, the cell’s main fuel.
*Ion channels ➥ these are tiny gates in a cell’s outer wall that open and close to let charged particles like sodium, potassium, calcium, or chloride move in or out. By controlling that flow, cells send signals, make muscles contract, and keep the right balance of salt and water.
*Redox balance ➥ redox is short for reduction and oxidation, which are reactions where electrons are passed around. Redox balance means the cell has a healthy middle ground between oxidants and antioxidants, enough to run chemistry and signaling but not so much oxidant stress that parts get damaged.
* Mitochondrial complexes ➥ are five linked protein “stations” in the inner mitochondrial membrane that pass along energy to generate ATP, the cell’s fuel.
*Reactive oxygen species (ROS) ➥ chemically restless forms of oxygen that cells make as a byproduct of using oxygen for energy and signaling. They are very reactive, and in excess they can nick DNA, proteins, and fats, contributing to wear and tear called oxidative stress.
*GABA-A ➥ It’s a calming switch on brain cells. When the chemical GABA lands on a GABA-A receptor, it opens a tiny gate that lets chloride ions flow into the cell. That makes the cell less excitable (think anxiety and panic), which quiets brain activity.
💊Medications in the fluoroquinolone class (incl: Cipro/ciprofloxacin, Levaquin (off market)/levofloxacin, Avelox/moxifloxacin etc) in all forms for humans and pets: https://fq100.org/drug-list
🟥 Start here ➦ For tests and more info: https://fq100.org/find-help
📌 How to Find the Right Practitioner: https://fq100.org/find-medical
⚠️DISCLAIMER: No standalone test confirms fluoroquinolone toxicity, and none of the listed tests make the diagnosis, but are provided for general information and as a discussion with a physician. Test choices and interpretations should be made by a licensed clinician as Fluoroquinolone Toxicity Study does not provide medical advice. We do our best to provide accurate information.
References:
Do antibiotics cause mitochondrial and immune cell dysfunction? A literature review
https://academic.oup.com/jac/article/77/5/1218/6535933
Ciprofloxacin impairs mitochondrial DNA replication initiation through inhibition of Topoisomerase 2
https://academic.oup.com/nar/article/46/18/9625/5088042
Bactericidal Antibiotics Induce Mitochondrial Dysfunction and Oxidative Damage in Mammalian Cells
https://pmc.ncbi.nlm.nih.gov/articles/PMC3760005/
Pharmacokinetic prediction of levofloxacin accumulation in tissue and its association to tendinopathy
https://www.researchgate.net/publication/263808216_Pharmacokinetic_Prediction_of_Levofloxacin_Accumulation_in_Tissue_and_Its_Association_in_Tendinopathy
Oxidative stress induced by fluoroquinolones on treatment for complicated urinary tract infections in Indian patients
https://pubmed.ncbi.nlm.nih.gov/22224037/
Determination of the Excitatory Potencies of Fluoroquinolones in the Central Nervous System by an In Vitro Model
https://pmc.ncbi.nlm.nih.gov/articles/PMC105691/
Effects of Magnesium, Calcium, and Aluminum Chelation on Fluoroquinolone Absorption Rate and Bioavailability: A Computational Study
https://pmc.ncbi.nlm.nih.gov/articles/PMC8143323/
