Keflex Side Effects

Generic Name: cephalexin

Please note - some side effects for Keflex may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Keflex - for the Consumer

Keflex

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Keflex:

Diarrhea; dizziness; headache; indigestion; joint pain; stomach pain; tiredness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; confusion; dark urine; decreased urination; fever; hallucinations; red, swollen, or blistered skin; seizures; severe or bloody diarrhea; severe stomach pain or cramps; severe tiredness; unusual bruising or bleeding; unusual vaginal pain, odor, or discharge; yellowing of the eyes or skin.

Keflex Suspension

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Keflex Suspension:

Diarrhea; dizziness; headache; indigestion; joint pain; stomach pain; tiredness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; confusion; dark urine; decreased urination; fever; hallucinations; red, swollen, or blistered skin; seizures; severe or bloody diarrhea; severe stomach pain or cramps; severe tiredness; unusual bruising or bleeding; unusual vaginal pain, odor, or discharge; yellowing of the eyes or skin.

Keflex Side Effects - for the Professional

Keflex

Gastrointestinal— Onset of pseudomembranous colitis may occur during or after antibacterial treatment. Nausea and vomiting have been reported rarely. The most frequent side effect has been diarrhea. It was very rarely severe enough to warrant cessation of therapy. Dyspepsia, gastritis, and abdominal pain have also occurred. As with some penicillins and some other cephalosporins, transient hepatitis and cholestatic jaundice have been reported rarely.

Hypersensitivity— Allergic reactions in the form of rash, urticaria, angioedema, and, rarely, erythema multiforme, Stevens-Johnson syndrome, or toxic epidermal necrolysis have been observed. These reactions usually subsided upon discontinuation of the drug. In some of these reactions, supportive therapy may be necessary. Anaphylaxis has also been reported.

Other reactions have included genital and anal pruritus, genital moniliasis, vaginitis and vaginal discharge, dizziness, fatigue, headache, agitation, confusion, hallucinations, arthralgia, arthritis, and joint disorder. Reversible interstitial nephritis has been reported rarely. Eosinophilia, neutropenia, thrombocytopenia, hemolytic anemia, and slight elevations in AST and 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 altered laboratory tests have been reported for cephalosporin class antibiotics:

 

Adverse Reactions— Fever, colitis, aplastic anemia, hemorrhage, renal dysfunction, and toxic nephropathy.

 

Several cephalosporins have been implicated in triggering seizures, particularly in patients with renal impairment when the dosage was not reduced. If seizures associated with drug therapy should occur, the drug should be discontinued. Anticonvulsant therapy can be given if clinically indicated.

 

Altered Laboratory Tests— Prolonged prothrombin time, increased BUN, increased creatinine, elevated alkaline phosphatase, elevated bilirubin, elevated LDH, pancytopenia, leukopenia, and agranulocytosis.

Side Effects by Body System

General

Cephalexin is generally well-tolerated. Large studies report an overall 6% incidence of side effects, some of which may not be related to cephalexin.

Hypersensitivity

Up to 20% of patients with a penicillin allergy may be allergic to cephalexin.

Hypersensitivity reactions have included fever, urticaria, rash, eosinophilia, anaphylaxis, angioedema, contact dermatitis, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, acute paronychia, and hepatitis.

Gastrointestinal

Gastrointestinal side effects have included diarrhea, nausea, vomiting, dyspepsia, abdominal cramping, anorexia, and anal pruritus. Diarrhea due to Clostridium difficile colitis has been reported with some cephalosporins.

If diarrhea occurs and it does not resolve with discontinuation of the drug and/or institution of standard antidiarrheal therapy, pseudomembranous colitis should be suspected.

Hepatic

Hepatic side effects have included transient elevations of liver function tests, transient hepatitis, and rare cases of cholestatic jaundice.

Renal

Renal side effects have rarely included interstitial nephritis. Reversible fever, azotemia, pyuria and eosinophiluria are the hallmarks of cephalosporin-induced interstitial nephritis. Acute tubular necrosis has also been reported.

Hematologic

Hematologic side effects have included eosinophilia, neutropenia, thrombocytopenia and hemolytic anemia.

Nervous system

Nervous system side effects have included dizziness, fatigue, headache, agitation, confusion, and hallucinations. Reversible ototoxicity and vertigo, apparently due to labyrinthine disease, have been reported in a few patients with renal disease.

Genitourinary

Genitourinary side effects have included genital pruritus, genital moniliasis, vaginitis, and vaginal discharge.

Musculoskeletal

Musculoskeletal side effects have included arthralgia, arthritis, and joint disorder.

Dermatologic

Dermatologic side effects have included urticaria, rash, contact dermatitis, erythema multiforme, and toxic epidermal necrolysis.

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