Levaquin vs. Keflex: What’s the difference?
- Levaquin (levofloxacin) and Keflex (cephalexin) are antibiotics used to treat bacterial infections of the sinuses, skin, lungs, ears, airways, bones, joints and urinary tract.
- Levaquin (levofloxacin) is also used to treat prostatitis; infectious diarrhea caused by E. coli, Campylobacter jejuni, and Shigella; obstetric infections, including mastitis (infection of the breast); inhalational anthrax exposure; and to prevent and treat plague caused by Yersinia pestis.
- Levaquin and Keflex are different types of antibiotics. Levaquin is a fluoroquinolone antibiotic and Keflex is a cephalosporin antibiotic.
- Side effects of Levaquin and Keflex that are similar include nausea, vomiting, diarrhea, headache, dizziness, abdominal pain, and skin rash.
- Side effects of Levaquin that are different from Keflex include constipation, difficulty sleeping, gas, and itching.
- Levaquin and other fluoroquinolone antibiotics have been associated with tendinitis and even rupture of tendons, particularly the Achilles tendon.
- Side effects of Keflex that are different from Levaquin include fever, abnormal liver tests, and vaginitis.
What is Levaquin? What is Keflex?
Levaquin (levofloxacin) is a fluoroquinolone antibiotic used to treat bacterial infections of the skin, lungs, airways, sinuses, ears, bones, and joints; prostatitis; urinary infections; infectious diarrhea caused by E. coli, Campylobacter jejuni, and Shigella; obstetric infections, including mastitis (infection of the breast); inhalational anthrax exposure; and to prevent and treat plague caused by Yersinia pestis. Levaquin stops bacteria from multiplying by preventing the reproduction and repair of their genetic material, DNA. It is in the fluoroquinolone class of antibiotics that also includes ciprofloxacin (Cipro), norfloxacin (Noroxin), ofloxacin (Floxin), trovafloxacin (Trovan), and lomefloxacin (Maxaquin).
Keflex (cephalexin) is a cephalosporin antibiotic, similar to penicillin in action and side effects. Bacteria susceptible to Keflex include Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, E. coli, and others. Common infections Keflex treats include middle ear (otitis media), tonsillitis, throat, laryngitis, bronchitis, pneumonia, urinary tract (UTIs), skin, and bone.
What are the side effects of Levaquin and Keflex?
Serious side effects and warnings include:
- Levofloxacin as well as other antibiotics in the fluoroquinolone class of antibiotics have been associated with tendinitis and even rupture of tendons, particularly the Achilles tendon.
- Fluoroquinolones have neuromuscular blocking activity and can worsen muscle weakness in individuals with myasthenia gravis.
- The most frequently reported side effects are:
- Nausea or vomiting
Less common side effects include:
Rare allergic reactions have been described are:
What are the serious side effects (adverse effects) of levofloxacin
Possible serious side effects of levofloxacin include:
Other serious side effects and adverse events of levofloxacin include:
- Levofloxacin should be used with caution in patients with central nervous system diseases such as seizures, because rare seizures have been reported in patients receiving Levaquin.
- Levofloxacin should be avoided in children and adolescents less than 18 years of age, as safe use in these patients has not been established.
- Many antibiotics, including levofloxacin, can alter the normal bacteria in the colon and encourage overgrowth of a bacterium responsible for the development of inflammation of the colon, (C. difficile or pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting Levaquin (diarrhea, fever, abdominal pain, and possibly shock) should contact their doctor immediately.
- Patients taking Levofloxacin can develop sensitivity of the skin to direct sunlight (photosensitivity) and should avoid exposure to sunlight or use sunblock.
- Fluoroquinolones worsen low blood glucose levels when combined with sulfonylureas (for example, glyburide [Micronase, Diabeta, Glynase, Prestab]).
- Because of serious side effects associate with fluoroquinolones, they should not be used for treating uncomplicated urinary tract infections, acute bacterial exacerbation of chronic bronchitis or acute bacterial sinusitis unless there are no other alternatives.
The most common side effects of cephalexin are:
- abdominal pain,
- skin rash,
- abnormal liver tests, and
Individuals who are allergic to penicillin may also be allergic to cephalexin. Serious but rare reactions include seizures, severe allergic reactions (anaphylaxis), and low platelet or red blood cell count.
Cephalexin, like almost all antibiotics, may cause mild or severe cases of pseudomembranous colitis, a mild to severe inflammation of the colon. Antibiotics, including cephalexin alter the types of bacteria in the colon and permit overgrowth of a bacterium called Clostridium difficile. Studies indicate that toxins produced by Clostridium difficile are a primary cause of pseudomembranous colitis.
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What is the dosage of Levaquin vs. Keflex?
- The usual dose is 250-750 mg given once daily for 3-14 days depending on the type of infection.
- Anthrax is treated with 500 mg daily for 60 days.
- It is important to take oral formulations at least 2 hours before or 2 hours after any antacid or mineral supplement containing iron, calcium, zinc, or magnesium since these bind Levaquin and prevent its absorption into the body.
- The dose of cephalexin for adults is 1 to 4 grams in divided doses.
- The usual adult dose is 250 mg every 6 hours.
- Some infections may be treated with 500 mg every 12 hours.
- Children are treated with 25-100 mg/kg/day in divided doses.
- The dosing interval may be every 6 or 12 hours depending on the type and seriousness of the infection.
What drugs interact with Levaquin and Keflex?
- Iron, calcium, zinc, or magnesium can attach to levofloxacin and other fluoroquinolones and prevent their absorption from the intestine into the blood. Therefore, products (for example, antacids) that contain iron, calcium, zinc, or magnesium should be taken at least 2 hours before or 2 hours after levofloxacin. Other drugs that contain these minerals and can similarly interact with levofloxacin include sucralfate (Carafate) and didanosine (Videx, Videx EC).
- Taking nonsteroidal anti-inflammatory drugs (NSAIDs) with levofloxacin may increase the risk of central nervous stimulation, resulting in over-excitation. There have been reports of changes in blood sugar (increases and decreases) in patients treated with fluoroquinolones and antidiabetic agents.
- Fluoroquinolones may increase the effect of warfarin (Coumadin, Jantoven).
Are Levaquin and Keflex safe to use while pregnant and breastfeeding?
- Levaquin is not recommended for use in pregnant women since Levaquin causes joint and bone deformities in juvenile animals of several species.
- Levaquin is excreted in breast milk. Mothers should decide whether to stop breastfeeding or discontinue Levaquin.
Cephalexin is excreted in breast milk. Cephalexin should be used with caution or stopped when breastfeeding.
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Medically Reviewed on 4/1/2019
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