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Floxin Side Effects

Generic Name: ofloxacin

Note: This page contains information about the side effects of ofloxacin. Some of the dosage forms included on this document may not apply to the brand name Floxin.

For the Consumer

Applies to ofloxacin: oral tablet

In addition to its needed effects, some unwanted effects may be caused by ofloxacin (the active ingredient contained in Floxin). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking ofloxacin:

Less common:
  • Abdominal or stomach pain
  • anxiety
  • black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • blurred vision
  • body aches or pain
  • chest pain
  • chills
  • cloudy urine
  • cold sweats
  • coma
  • confusion
  • congestion
  • cool, pale skin
  • cough
  • depression
  • diarrhea
  • dry mouth
  • dryness or soreness of the throat
  • eye pain
  • fast heartbeat
  • fever
  • flushed, dry skin
  • fruit-like breath odor
  • general feeling of illness
  • headache
  • hoarseness
  • increased hunger
  • increased thirst
  • increased urination
  • lower back or side pain
  • nausea
  • nervousness
  • nightmares
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • pus in the urine
  • runny nose
  • seizures
  • shakiness
  • shortness of breath
  • slurred speech
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sweating
  • swollen glands
  • tender, swollen glands in the neck
  • trouble with swallowing
  • troubled breathing with exertion
  • unexplained weight loss
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • voice changes
  • vomiting
  • Burning while urinating
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • change in color vision
  • continuing ringing or buzzing or other unexplained noise in the ears
  • convulsions
  • decrease in frequency of urination
  • decrease in urine volume
  • decreased hearing or any change in hearing
  • difficult or painful urination
  • difficulty in passing urine (dribbling)
  • difficulty seeing at night
  • difficulty with moving
  • discouragement
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • false or unusual sense of well-being
  • fast, irregular, pounding, or racing heartbeat or pulse
  • fear or nervousness
  • feeling of constant movement of self or surroundings
  • feeling of warmth or heat
  • feeling sad or empty
  • flushing or redness of the skin, especially on the face and neck
  • hearing loss
  • hives or welts
  • increased need to urinate
  • increased sensitivity of the eyes to sunlight
  • increased sweating
  • irritability
  • itching
  • joint pain
  • lack of appetite
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • loss of bladder control
  • loss of interest or pleasure
  • muscle aching or cramping
  • muscle pains or stiffness
  • muscle spasm or jerking of all extremities
  • no blood pressure or pulse
  • no breathing
  • passing urine more often
  • pounding in the ears
  • redness, soreness, or itching skin
  • seeing, hearing, or feeling things that are not there
  • sensation of spinning
  • shakiness in the legs, arms, hands, or feet
  • skin rash
  • slow or fast heartbeat
  • sores, welting, or blisters
  • stopping of the heart
  • sudden loss of consciousness
  • swelling
  • swollen joints
  • trembling or shaking of the hands or feet
  • trouble concentrating
  • trouble performing routine tasks
  • trouble sleeping
  • unconsciousness
Incidence not known:
  • Abdominal or stomach tenderness
  • actions that are out of control
  • back, leg, or stomach pains
  • blistering, peeling, or loosening of the skin
  • bloating
  • blue lips and fingernails
  • burning, dry, or itching eyes
  • changes in behavior
  • confusion about identity, place, and time
  • coughing that sometimes produces a pink frothy sputum
  • coughing up blood
  • cracks in the skin
  • crying
  • dark-colored urine
  • darkening of the skin
  • delusions of persecution, mistrust, suspiciousness, and/or combativeness
  • depersonalization
  • diarrhea, watery and severe, which may also be bloody
  • difficulty with breathing, chewing, or talking
  • difficulty with speaking
  • difficulty with swallowing
  • discharge or excessive tearing
  • double vision
  • drooling
  • drooping eyelids
  • dysphoria
  • euphoria
  • feeling of discomfort
  • general body swelling
  • heartburn
  • high fever
  • hyperventilation
  • increased blood pressure
  • increased menstrual flow or vaginal bleeding
  • increased sensitivity of the skin to sunlight
  • increased sweating
  • indigestion
  • inflammation of the joints
  • irregular heartbeats
  • irregular or slow heart rate
  • itching of the vagina or outside the genitals
  • loss of ability to use or understand speech or language
  • loss of appetite
  • loss of balance control
  • loss of heat from the body
  • mental depression
  • mood or mental changes
  • muscle weakness
  • noisy breathing
  • nosebleeds
  • numbness of the hands
  • pain during sexual intercourse
  • pain in the ankles or knees
  • pain, inflammation, or swelling in the calves, shoulders, or hands
  • painful, red lumps under the skin, mostly on the legs
  • paralysis
  • prolonged bleeding from cuts
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • quick to react or overreact emotionally
  • rapidly changing moods
  • rash
  • red or black, tarry stools
  • red or dark brown urine
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • red, swollen skin
  • redness or other discoloration of the skin
  • redness, pain, or swelling of the eye, eyelid, or inner lining of the eyelid
  • restlessness
  • scaly skin
  • severe abdominal pain, cramping, or burning
  • severe sunburn
  • severe tiredness
  • shaking
  • shuffling walk
  • stiffness of the limbs
  • stomach pain, continuing
  • swelling of the face, fingers, or lower legs
  • swollen lymph glands
  • talking, feeling, and acting with excitement
  • thick, white, curd-like vaginal discharge without odor or with mild odor
  • thoughts of killing oneself
  • twisting movements of the body
  • uncontrolled eye movements
  • uncontrolled movements, especially of the face, neck, and back
  • unexplained bleeding or bruising
  • unpleasant breath odor
  • unsteadiness or awkwardness
  • unusual behavior, such as disorientation to time or place, failure to recognize people, hyperactivity, or restlessness, especially in children using 2% cyclopentolate
  • unusual weight loss
  • upper right abdominal pain
  • vomiting of blood or material that looks like coffee grounds
  • weakness in the arms, hands, legs, or feet
  • weight gain
  • wheezing
  • yellowing of the eyes or skin

Minor Side Effects

Some of the side effects that can occur with ofloxacin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Sleeplessness
  • unable to sleep
Less common:
  • Change in taste
  • excess air or gas in the stomach or intestines
  • full feeling
  • loss of taste
  • passing gas
  • runny nose

For Healthcare Professionals

Applies to ofloxacin: intravenous solution, oral tablet


Ofloxacin therapy was generally well tolerated, and side effects were mild in nature. In clinical trials, 11% of patients experienced side effects. Discontinuation of ofloxacin (the active ingredient contained in Floxin) therapy due to side effects occurred in 4% of patients.[Ref]


Common (1% to 10%): Nausea (up to 10%), diarrhea (up to 4%), vomiting (up to 4%), dysgeusia (up to 3%), abdominal pain and cramps (up to 3%), dry mouth (up to 3%), flatulence (up to 3%), gastrointestinal distress (up to 3%), constipation (up to 3%)
Uncommon (0.1% to 1%): Dyspepsia (less than 1%)
Postmarketing reports: Pseudomembranous colitis, gastrointestinal hemorrhage, intestinal perforation, hiccough, pyrosis, painful oral mucosa[Ref]

Onset of pseudomembranous colitis may occur during or after therapy.[Ref]

Nervous system

Common (1% to 10%): Headache (up to 9%), dizziness (up to 5%)
Uncommon (0.1% to 1%): Seizures (less than 1%), paresthesia (less than 1%), syncope (less than 1%), vertigo (less than 1%), tremor (less than 1%), decreased hearing acuity (less than 1%), tinnitus (less than 1%)
Frequency not reported: Idiopathic intracranial hypertension
Postmarketing reports: Peripheral neuropathy (may be irreversible), ataxia, incoordination, exacerbation of myasthenia gravis, exacerbation of extrapyramidal disorders, dysphasia, lightheadedness, syncope[Ref]

Seizures are more likely to occur in elderly patients and in those with renal insufficiency.

One survey reported 6 cases of peripheral neuropathy associated with ofloxacin. In one case, a 49-year-old female developed diffuse numbness, "pins and needles" sensation, burning pain, memory loss, visual impairment, joint pain, palpitations, altered sense of smell, insomnia, tinnitus, and severe panic attacks, with some symptoms persisting after 3 years.[Ref]


Common (1% to 10%): Increased creatinine (1% or more), increased BUN (1% or more)
Frequency not reported: Nephrogenic diabetic insipidus
Postmarketing reports: Renal calculi, renal failure, interstitial nephritis[Ref]


Common (1% to 10%): Elevated alkaline phosphatase (1% or more), elevated AST (1% or more), elevated ALT (1% or more)
Postmarketing reports: Hepatic dysfunction (including hepatic necrosis, jaundice [cholestatic or hepatocellular], hepatitis), hepatic failure (including fatal cases), elevated liver function tests (including GGTP, LDH, bilirubin)[Ref]


Common (1% to 10%): Anemia (1% or more), leukopenia (1% or more), leukocytosis (1% or more), neutropenia (1% or more), neutrophilia (1% or more), increased band forms (1% or more), lymphocytopenia (1% or more), eosinophilia (1% or more), lymphocytosis (1% or more), thrombocytopenia (1% or more), thrombocytosis (1% or more), elevated ESR (1% or more)
Postmarketing reports: Anemia (including hemolytic and aplastic), hemorrhage, pancytopenia, agranulocytosis, leukopenia, reversible bone marrow depression, thrombocytopenia, thrombotic thrombocytopenic purpura, petechiae, prothrombin time prolongation, purpura, ecchymosis/bruising[Ref]


IV formulation:
Common (1% to 10%): Injection site reactions (including phlebitis, swelling, erythema; about 2%)[Ref]


Uncommon (0.1% to 1%): Arthralgia (less than 1%), myalgia (less than 1%)
Postmarketing reports: Tendonitis, tendon rupture, weakness, rhabdomyolysis[Ref]


Ofloxacin (the active ingredient contained in Floxin) was associated with 2 cases of torsade de pointes reported to the FDA between 1996 and 2001.[Ref]

Uncommon (0.1% to 1%): Cardiac arrest (less than 1%), hypertension (less than 1%), hypotension (less than 1%), palpitations (less than 1%), vasodilation (less than 1%)
Postmarketing reports: Cerebral thrombosis, tachycardia, hypotension/shock, torsades de pointes[Ref]


Uncommon (0.1% to 1%): Vasculitis (less than 1%)
Postmarketing reports: Anaphylactic reactions/shock, anaphylactoid reactions/shock, serum sickness[Ref]


Common (1% to 10%): External genital pruritus in women (up to 6%), vaginitis (up to 5%), vaginal discharge (up to 3%), glucosuria (1% or more), proteinuria (1% or more), alkalinuria (1% or more), hyposthenuria (1% or more), hematuria (1% or more), pyuria (1% or more)
Uncommon (0.1% to 1%): Dysuria (less than 1%), urinary frequency (less than 1%), urinary retention (less than 1%), dysmenorrhea (less than 1%), menorrhagia (less than 1%), metrorrhagia (less than 1%), burning, irritation, pain, and rash of the female genitalia (less than 1%)
Postmarketing reports: Vaginal candidiasis, albuminuria, candiduria, anuria, hematuria, polyuria, crystalluria, cylindruria[Ref]

Crystalluria and cylindruria have been reported with other quinolones.[Ref]


Common (1% to 10%): Rash (up to 3%), pruritus (up to 3%)
Uncommon (0.1% to 1%): Angioedema (less than 1%), diaphoresis (less than 1%), urticaria (less than 1%)
Postmarketing reports: Hyperpigmentation, erythema multiforme/Stevens-Johnson syndrome, erythema nodosum, exfoliative dermatitis, toxic epidermal necrolysis, photosensitivity/phototoxicity reaction, vesiculobullous eruption[Ref]

A 75-year-old male developed toxic epidermal necrolysis and died of complications after receiving a total of 23.6 grams of oral ofloxacin over 51 days.[Ref]


Common (1% to 10%): Visual disturbances (up to 3%)
Uncommon (0.1% to 1%): Photophobia (less than 1%)
Postmarketing reports: Diplopia, nystagmus, blurred vision, conjunctivitis, ophthalmologic abnormalities (including cataracts, multiple punctate lenticular opacities)[Ref]

Ophthalmologic abnormalities (including cataracts and multiple punctate lenticular opacities) have been reported with other quinolones.[Ref]


Common (1% to 10%): Fatigue (up to 3%), chest pain (up to 3%), fever (up to 3%), trunk pain (up to 3%)
Uncommon (0.1% to 1%): Asthenia (less than 1%), chills (less than 1%), malaise (less than 1%), edema (less than 1%), extremity pain (less than 1%), pain (less than 1%)
Postmarketing reports: Reversible disturbances of taste, smell, hearing, and equilibrium[Ref]


Uncommon (0.1% to 1%): Respiratory arrest (less than 1%), cough (less than 1%), rhinorrhea (less than 1%), epistaxis (less than 1%)
Postmarketing reports: Dyspnea, bronchospasm, allergic pneumonitis, pulmonary edema, stridor[Ref]


Common (1% to 10%): Decreased appetite (up to 3%), hyperglycemia (1% or more), hypoglycemia (1% or more)
Uncommon (0.1% to 1%): Thirst (less than 1%), weight loss (less than 1%)
Postmarketing reports: Hypoglycemia, hyperglycemia, acidosis, elevated serum triglycerides, elevated serum cholesterol, elevated serum potassium[Ref]

Hypoglycemia and hyperglycemia have been reported, especially in diabetic patients on insulin or oral hypoglycemic agents.[Ref]


In one patient, a psychotic reaction to ofloxacin (the active ingredient contained in Floxin) presented with irritability, restlessness, insomnia, and irrational fear. The reaction was treated with haloperidol and resolved within 48 hours. One study suggests that the CNS effects of quinolones may be due to an interaction with the benzodiazepine-GABA receptor complex and may be controlled by benzodiazepine administration.[Ref]

Common (1% to 10%): Insomnia (up to 7%), nervousness (up to 3%), sleep disorders (up to 3%), somnolence (up to 3%)
Uncommon (0.1% to 1%): Anxiety (less than 1%), cognitive change (less than 1%), depression (less than 1%), dream abnormality (less than 1%), euphoria (less than 1%), hallucinations (less than 1%), confusion (less than 1%)
Postmarketing reports: Agitation, restlessness, nightmares, suicidal thought or acts, disorientation, psychotic reactions, paranoia, phobia, aggressiveness/hostility, manic reaction, emotional lability[Ref]


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Not all side effects for Floxin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.