ConditionWhole body & general
Antibiotic Toxicity and Antimicrobial Poisoning
Antibiotic toxicity is harm caused by an antibiotic, antifungal, antiviral or antiparasitic medicine, either from an overdose or from a normal dose that builds up, for example when the kidneys are not clearing it. Most single overdoses of common antibiotics such as amoxicillin cause only vomiting and diarrhea. A few drugs, including isoniazid, aminoglycosides, chloroquine and dapsone, can cause seizures, kidney failure, hearing loss or heart rhythm problems. Call Poison Control (1-800-222-1222 in the US) for any suspected overdose.
Also called: Antibiotic poisoning, antimicrobial overdose, antibiotic overdose, drug toxicity from antibiotics
At a glance
- What it is
- Harm from too much of an antimicrobial medicine, or from a dose the body cannot clear.
- Common symptoms
- Nausea, vomiting, diarrhea and stomach pain.
- Serious effects
- Seizures, kidney injury, hearing loss, irregular heartbeat, liver injury, low oxygen in the blood.
- What to do
- Call Poison Control or 911. Bring the medicine packaging.
- Treatment
- Supportive care, activated charcoal in some cases, specific antidotes (such as vitamin B6 for isoniazid), and dialysis for some drugs.
When to get help
Call 911 or go to the ER
- A seizure, collapse, or difficulty waking up after taking an antimicrobial
- Swelling of the face, lips or throat, wheezing or trouble breathing (anaphylaxis)
- Fainting, a racing or irregular heartbeat, or chest pain
- Blue or gray lips and skin with breathlessness (possible methemoglobinemia from dapsone or primaquine)
- A child who has swallowed adult tablets of isoniazid, chloroquine, hydroxychloroquine or dapsone, even if they seem well
- A blistering, peeling rash with sores in the mouth or eyes
See a doctor within a day or two
- Passing much less urine than usual while on an antibiotic, especially vancomycin or gentamicin
- New ringing in the ears, hearing loss or dizziness during treatment
- Severe watery diarrhea, more than 3 times a day, with fever or belly cramps, during or after antibiotics
- Yellowing skin or eyes, dark urine or pale stools
- Any accidental double dose in someone with kidney disease
Book a routine appointment
- Mild nausea or loose stools on a normal dose
- Tingling or numbness in the feet during long courses (for example isoniazid, linezolid or metronidazole)
What to do right now
- If the person is unconscious, having a seizure or struggling to breathe, call 911 or your local emergency number.
- Otherwise call Poison Control at 1-800-222-1222 (US), or your local poison center. They advise on whether home observation is safe.
- Have the packaging ready: drug name, strength, number of tablets missing and the time taken.
- Do not make the person vomit. It does not help and can cause choking.
- Do not give "remedies" such as milk, salt water or herbal treatments. There is no home remedy for antibiotic poisoning.
Symptoms of antibiotic toxicity
Symptoms depend on the drug, the dose and the person's kidney and liver function.
General symptoms of overdose
- nausea, vomiting and stomach cramps
- diarrhea
- headache and dizziness
- drowsiness or agitation
Organ-specific effects
| Drug group | Main toxic effects |
|---|---|
| Penicillins and cephalosporins | Usually mild stomach upset. Very high doses can cause seizures, especially with kidney failure |
| Aminoglycosides (gentamicin, tobramycin, amikacin) | Kidney injury, permanent hearing loss, balance problems |
| Vancomycin | Kidney injury. Flushing ("red man" or vancomycin infusion reaction) if infused too fast |
| Fluoroquinolones (ciprofloxacin, levofloxacin) | Tendon rupture, nerve damage, confusion, irregular heart rhythm, blood sugar swings |
| Macrolides (azithromycin, erythromycin) | Stomach upset, irregular heart rhythm (prolonged QT) |
| Isoniazid (tuberculosis) | Seizures that do not respond to usual medicine, acidosis, coma, liver injury |
| Chloroquine and hydroxychloroquine | Dangerous heart rhythm problems, low potassium, low blood pressure. Very toxic to children in small amounts |
| Dapsone | Methemoglobinemia (blood cannot carry oxygen), hemolysis |
| Metronidazole | Nerve damage, rarely brain toxicity with long courses; reaction with alcohol |
| Linezolid | Low blood counts, nerve damage, serotonin syndrome with some antidepressants |
| Antifungals (amphotericin B, azoles) | Kidney injury and low potassium (amphotericin), liver injury (azoles) |
| Acyclovir | Kidney injury from crystals, confusion |
Reactions that are not dose-related
Many serious problems blamed on "antibiotic poisoning" are actually allergic or immune reactions that can happen at a normal dose:
- anaphylaxis within minutes to an hour
- rashes, including rare but serious Stevens-Johnson syndrome
- serum sickness-like reactions with joint pain and fever
- drug-induced liver injury, for example from amoxicillin-clavulanate
- C. difficile colitis, causing pseudomembranous colitis with severe diarrhea
Who is most at risk
- Young children, who may swallow tablets meant for adults
- People with kidney disease, because many antibiotics are cleared by the kidneys and accumulate
- Older adults, who often take several interacting medicines
- People on long or high-dose courses, such as for tuberculosis, bone infections or endocarditis
- People with G6PD deficiency, who can develop hemolysis with dapsone, primaquine, nitrofurantoin and some sulfa drugs
How it is diagnosed
The doctor will ask what was taken, how much and when, and about kidney or liver disease. Tests may include:
- kidney function (creatinine), electrolytes and liver tests
- blood levels of the drug (routine for vancomycin and aminoglycosides)
- an ECG to look for a prolonged QT interval
- blood gas and methemoglobin level if lips look blue
- hearing tests during long aminoglycoside courses
Treatment
There is no general antidote. Care focuses on support and removing or neutralizing the drug:
- Monitoring, fluids and anti-nausea medicine for mild cases
- Activated charcoal, given by medical staff within about 1 to 2 hours for some dangerous overdoses
- Pyridoxine (vitamin B6) for isoniazid seizures
- Methylene blue for methemoglobinemia from dapsone
- Benzodiazepines for seizures, and careful heart monitoring and potassium replacement for chloroquine
- Hemodialysis to remove certain drugs, such as aminoglycosides, in people with kidney failure
- Stopping the drug and switching to a safer alternative for allergic or organ reactions
Prevention
- Store all medicines up high and locked, away from children.
- Take exactly the prescribed dose. If you miss a dose, do not double up unless your pharmacist advises it.
- Tell every prescriber about kidney or liver disease and all other medicines you take.
- Keep appointments for blood tests during long courses.
- Do not take leftover antibiotics or someone else's prescription.
Frequently asked questions
What are the symptoms of antibiotic toxicity?
The most common are nausea, vomiting, diarrhea and stomach pain. More serious toxicity depends on the drug and can include seizures, kidney injury with reduced urine, ringing in the ears or hearing loss, an irregular heartbeat, yellowing of the skin and, rarely, blue-gray skin from low blood oxygen.
What happens if you take too many antibiotics at once?
With common antibiotics like amoxicillin, an accidental extra dose usually causes only stomach upset. Some antimicrobials are much more dangerous in overdose, including isoniazid, chloroquine and dapsone. Call Poison Control for advice whenever someone takes more than prescribed.
Are there home remedies for antibiotic poisoning?
No. Do not induce vomiting or give milk, charcoal or herbal remedies at home. Call Poison Control or 911. Medical treatment may include monitoring, activated charcoal given in hospital, specific antidotes or dialysis, depending on the drug.
Can antibiotics damage your kidneys?
Yes, some can, especially vancomycin, aminoglycosides, amphotericin B and high-dose acyclovir. The risk is higher with dehydration, older age and existing kidney disease. Doctors check kidney blood tests and drug levels during treatment with these medicines.
Sources
This guide was written from current patient and clinical guidance, including:
- America's Poison Centers: Poison Help
- MedlinePlus: Drug reactions; Antibiotics
- National Library of Medicine LiverTox: Antibiotics
- Merck Manual Professional Version: Overview of antibacterial drugs
- CDC: Antibiotic safety