What is Keflex (cephalexin)?
Keflex (cephalexin) is a cephalosporin antibiotic used to treat infections caused by bacteria including middle ear infections (otitis media), tonsillitis, throat infections, laryngitis, bronchitis, pneumonia, urinary tract (UTIs), and skin and bone infections.
Drug interactions of Keflex include BCG and typhoid vaccines. There are no adequate and well-controlled studies of Keflex in pregnant women. Keflex should be used during pregnancy only if clearly needed. Keflex is excreted in breast milk. Keflex should be used with caution or stopped when breastfeeding.
What are the side effects of Keflex?
What are the common side effects of Keflex?
Common side effects of Keflex include
- abdominal pain,
- skin rash,
- abnormal liver tests, and
What are the serious side effects of Keflex?
Serious side effects of Keflex include
- mild or severe cases of pseudomembranous colitis (a mild to severe inflammation of the colon),
- Clostridium difficile (C. diff) infection, and
- allergic reactions.
Serious but rare allergic reactions include
What drugs interact with Keflex?
Careful patient monitoring and dose adjustment of metformin is recommended in patients concomitantly taking Keflex and metformin.
Interaction With Laboratory Or Diagnostic Testing
A false-positive reaction may occur when testing for the presence of glucose in the urine using Benedict's solution or Fehling's solution.
Keflex side effects list for healthcare professionals
The following serious events are described in greater detail in the Warning and Precautions section:
- Hypersensitivity reactions
- Clostridium difficile-associated diarrhea
- Direct Coombs' Test Seroconversion
- Seizure Potential
- Effect on Prothrombin Activity
- Development of Drug-Resistant Bacteria
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice
In clinical trials, the most frequent adverse reaction was diarrhea. Nausea and vomiting, dyspepsia, gastritis, and abdominal pain have also occurred. As with penicillins and other cephalosporins, transient hepatitis and cholestatic jaundice have been reported.
Other reactions have included hypersensitivity reactions, genital and anal pruritus, genital candidiasis, vaginitis and vaginal discharge, dizziness, fatigue, headache, agitation, confusion, hallucinations, arthralgia, arthritis, and joint disorder. Reversible interstitial nephritis has been reported. Eosinophilia, neutropenia, thrombocytopenia, hemolytic anemia, and slight elevations in aspartate transaminase (AST) and alanine transaminase (ALT) have been reported.
In addition to the adverse reactions listed above that have been observed in patients treated with Keflex, the following adverse reactions and other altered laboratory tests have been reported for cephalosporin class antibacterial drugs:
Other Adverse Reactions
Altered Laboratory Tests
Prolonged prothrombin time, increased blood urea nitrogen (BUN), increased creatinine, elevated alkaline phosphatase, elevated bilirubin, elevated lactate dehydrogenase (LDH), pancytopenia, leukopenia, and agranulocytosis.
Keflex (cephalexin) is a cephalosporin antibiotic used to treat infections caused by bacteria including middle ear infections (otitis media), tonsillitis, throat infections, laryngitis, bronchitis, pneumonia, urinary tract (UTIs), and skin and bone infections. Headaches, dizziness, and gastrointestinal side effects are common.
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Related Disease Conditions
Inner Ear Infection
An inner ear infection or otitis interna is caused by viruses or bacteria and can occur in both adults and children. An inner ear infection can cause symptoms and signs, for example, a severe ear, dizziness, vertigo, nausea and vomiting, and vertigo. An inner ear infection also may cause inflammation of the inner ear or labyrinthitis. Inner ear infections are not contagious; however, the bacteria and viruses that cause the infection can be transmitted to other people. Good hygiene practices will help decrease the chances of the infection spreading to others. Inner ear infection symptoms and signs like ear pain and nausea may be relieved with home remedies or over-the-counter (OTC) medication. Some inner ear infections will need to be treated and cured with antibiotics or prescription pain or antinausea medication.
Urinary Tract Infection (UTI)
A urinary tract infection (UTI) is an infection of the bladder, kidneys, ureters, or urethra. E. coli, a type of bacteria that lives in the bowel and near the anus, causes most UTIs. UTI symptoms include pain, abdominal pain, mild fever, urinary urgency, and frequency. Treatment involves a course of antibiotics.
Tonsillitis is a contagious infection with symptoms of bad breath, snoring, congestion, headache, hoarseness, laryngitis, and coughing up blood. Tonsillitis can be caused by acute infection of the tonsils, and several types of bacteria or viruses (for example, strep throat or mononucleosis). There are two types of tonsillitis, acute and chronic. Acute tonsillitis lasts from 1-2 weeks while chronic tonsillitis can last from months to years. Treatment of tonsillitis and adenoids include antibiotics, over-the-counter medications, and home remedies to relieve pain and inflammation, for example, saltwater gargle, slippery elm throat lozenges, sipping warm beverages and eating frozen foods (ice cream, popsicles), serrapeptase, papain, and andrographism Some people with chronic tonsillitis may need surgery (tonsillectomy or adenoidectomy).
Inner Ear Infection (Labyrinthitis)
Labyrinthitis occurs when there is inflammation of the part of the ear responsible for balance and hearing), usually due to viral infections of the inner ear. Learn about causes, symptoms, and treatment.
Middle Ear Infection (Otitis Media)
A middle ear infection (otitis media) can cause earache, temporary hearing loss, and pus drainage from the ear. It is most common in babies, toddlers, and young children. Learn about causes and treatment.
How Long Should a UTI Last After Antibiotics?
Depending on the severity of your UTI, you may need to take a 3-day, 7-day or even 2-week course of antibiotics. Since the bacteria causing your UTI can stay in your body even after symptoms are gone, it’s important to finish your entire course of antibiotics.
Ear Infection Home Treatment
Infections of the outer, middle, and inner ear usually are caused by viruses. Most outer (swimmer's ear) and middle ear (otitis media) infections can be treated at home with remedies like warm compresses for ear pain relief, tea tree, ginger, or garlic oil drops. Symptoms of an outer ear (swimmer's ear) and middle ear infection include mild to severe ear pain, pus draining from the ear, swelling and redness in the ear, and hearing problems. Middle and inner ear infections may cause fever, and balance problems. Inner ear infections also may cause nausea, vomiting, vertigo, ringing in the ear, and labyrinthitis (inflammation of the inner ear). Most outer and middle ear infections do not need antibiotics. Inner ear infections should be treated by a doctor specializing in ear and hearing problems.
Can You Flush Out a UTI With Water?
Patients with urinary tract infection (UTI) are usually advised to drink six to eight glasses (1.5 to 2 liters) of water every day to flush the infection out of the urinary system.
Is Tonsillitis Contagious?
Tonsillitis is a common infection, especially in kids. Tonsillitis is caused by viruses and bacteria like the flu and herpes simplex virus, and Streptococcus bacteria. These viruses and bacterium are spread person to person. Symptoms of tonsillitis are a yellow or white coating on the tonsils, throat pain, pain when swallowing, and hoarseness.
How Can I Treat a UTI While Pregnant Without Antibiotics?
What is a UTI? Learn what other treatments aside from antibiotics can help to relieve your UTI symptoms while pregnant.
Is a Urinary Tract Infection (UTI) Contagious?
Bacteria such as E. coli or Pseudomonas can cause a urinary tract infection (UTI). The incubation period for a UTI ranges from three to eight days.
How Do You Get Rid of an Inner Ear Infection Without Antibiotics?
What Is an Inner Ear Infection? Learn whether you need antibiotics and what other treatments can help to relieve your symptoms.
Will Tonsillitis Go Away on Its Own?
Tonsils are the two oval-shaped pads of tissue in the back of your throat. They help protect your body from infection. However, sometimes they get infected and inflamed (red and swollen) and this is called tonsillitis. Tonsillitis symptoms usually go away after three to four days.
Can UTI Symptoms Linger After Antibiotics?
Sometimes, UTI symptoms can linger even after antibiotic therapy. Reasons for this may be that your UTI is caused by an antibiotic-resistance strain of bacteria or caused by another type of bacteria, or you may have another condition entirely that causes UTI-like symptoms.
How Do You Know if Your Baby Has an Ear Infection?
Baby ear infection symptoms can include signs of irritability, tugging on the ears, an unpleasant smell and discharge coming from the ears, and more. Learn all the signs here.
Home Remedies for Tonsillitis: Treatment and Relief
Tonsillitis usually runs its course. Home remedies may help ease your/your child’s symptoms including getting plenty of rest, gargling, drinking water, washing your hands and taking over-the-counter pain relieving medication.
Can UTI Go Away by Itself?
Urinary tract infection, or UTI, is caused by the bacterial infection in any part of the urinary system, including kidneys, ureters, bladder and urethra. Symptoms typically include an increased urge to urinate with or without pain in the side and lower back. It is more common in women than in men because the urethra of females is shorter and closer to the anus.
What Is the Most Common Cause of Septic Arthritis in Kids?
Septic arthritis can be caused by bacterial, fungal or viral infections. Staphylococcus aureus, a type of bacteria, is the most common cause of septic arthritis in infants. Septic arthritis is a general term for any joint pain caused by infection of the joint.
How Do You Know If You Have Tonsillitis?
What is tonsillitis, and how do you know if you have it? Learn the signs of tonsillitis and what to do if you have it.
Can You Get UTI Antibiotics Over the Counter?
Currently, no urinary tract infection (UTI) antibiotics are available over the counter (OTC) in the United States. A person must consult a doctor to get the UTI treated with an antibiotic.
How Do You Get Rid of a UTI at Home?
What is a UTI? Learn whether you need antibiotics and what other home remedies can help to relieve your symptoms.
Treatment & Diagnosis
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Professional side effects list and drug interactions sections courtesy of the U.S. Food and Drug Administration