Side Effects of Cefpodoxime Proxetil for Dogs

Cefpodoxime proxetil, like cephalexin, is a cephalosporin and is one of the few that can be administered orally. Available for animal use since 2005, the veterinary formulation, Simplicef, is prescribed to treat dogs' skin, wound, bone, respiratory and bladder infections. It provides a broad range of activity against bacteria and is able to withstand anti-penicillin enzymes produced by Staphylococci bacterial strains and Escherichia coli. Simplicef is not effective against infections caused by parasites, intestinal worms, mites, viruses or fungi.


While generally safe and effective when used as prescribed, Cefpodoxime proxetil can cause side effects.

  1. Gastrointestinal Side Effects

    • Cefpodoxime "can be given on a full or empty stomach with no change in effectiveness," according to Wendy C. Brooks, DVM, but "approximately two percent of dogs taking this medication experience vomiting, one percent experience diarrhea, and one percent experience reduced appetite."

      Giving Cefpodoxime proxetil with a small amount of food may decrease some of the gastrointestinal side effects.

    Side Effects Related to Interactions with Drugs and Supplements

    • Antacids like ranitidine and cimetidine may decrease the absorption of cefpodoxime, so giving them together is contraindicated. Cefpdoxime proxetil should not be used in animals hypersensitive to cephalosporin or penicillin, as they may react negatively to both drugs.

      Doctors Foster and Smith suggest that pet owners consult with their veterinarian before using cephalosporins with vitamins, supplements, gentamicin, neomycin, the antifungal, amphotericin B or anticoagulants.

      Do not give cefpodoxime with probenicid, a drug used for reducing blood uric acid levels in hyperuricemic dogs. Cefpodoxime may increase blood levels and can cause gout and kidney stones.

    Overdose and Toxicity Side Effects

    • High doses or long-term use of cefpodoxime proxetil or Simplicef may result in liver disease and cause jaundice (yellowing of the gums or eyes). According to Doctors Foster and Smith, you should stop giving this drug and contact your veterinarian if you notice increased drinking and urination, indications of kidney damage, or other signs of overdose or toxicity, including muscle spasms or muscle weakness. Other results of toxicity and overdose are nervous system damage or "blood disorders, which may cause decreased white blood cells and platelets and an increased tendency to bruise or bleed."

    Allergic Side Effects

    • If you notice symptoms such as facial swelling, hives, scratching, sudden onset of diarrhea, vomiting, shock, seizures, pale gums, cold limbs, or coma, contact your veterinarian. Your dog may be experiencing an allergic reaction to Simplicef, cefpodoxime proxetil or cephalexin.

    Side Effects Related to Pregnancy and Lactation

    • Although no fetal abnormalities from cephalosporin use have been shown, it is best not to use these drugs in pregnant or lactating dogs. Cephalosporins may cross to fetuses or be passed to newborn puppies through the mother's milk, and what are mild side effects in adults could be very serious for puppies.

    Other Side Effects

    • Some dogs experience skin rashes, drooling or excitability when taking cephalopsorins. Rapid breathing is another rare side effect.

    Side Effects Related to Other Illnesses

    • High doses of cefpodoxime proxetil are not recommended for and must be used with caution when administering to dogs that may have epilepsy, seizures or kidney disease.

    Blood Related Side Effects

    • In very rare cases, blood dyscrasia or diseases of the blood-forming organs, including neutropenias, "may be seen following high doses of cephalosporins. Cephalosporin administration should be discontinued in such cases," according to the Simplicef warning label.

      This drug may cause an abnormal positive Coombs' test, falsely indicating the dog has antibodies that will act against red blood cells its body views as foreign.

    Side Effects that Affect Laboratory Testing

    • Cephalosporins may affect tests for urine glucose by causing false-positive results with test strips or dipsticks used to evaluate urine glucose levels.