Cefpodoxime

Cefpodoxime is a bactericidal antibiotic, a third-generation cephalosporin given by mouth. It works by preventing the building of the bacterial wall. To do this, it binds to the penicillin-binding proteins (PBPs), the enzymes that assemble peptidoglycan, the rigid framework of that wall. By blocking the transpeptidation step, it stops the bacterium from building its envelope, which causes it to die.

Bacteria can resist it through three main routes. Some produce beta-lactamases, enzymes that hydrolyze the antibiotic before it can act. Others alter their penicillin-binding proteins, the very target of the drug. Still others reduce the permeability of their wall, which limits the molecule from entering. The decision to prescribe cefpodoxime therefore depends on the susceptibility of the causative germ.

Cefpodoxime treats specific bacterial infections caused by susceptible germs. In the ENT and respiratory sphere, it is indicated for acute otitis media, pharyngitis or tonsillitis, sinusitis, community-acquired pneumonia, and exacerbation of bronchitis. These situations share bacteria that the molecule can reach at an effective concentration.

It also covers certain skin infections, uncomplicated urinary tract infections, and uncomplicated gonorrhea. In each case, its effectiveness rests on the susceptibility of the responsible bacterium, which the physician assesses before prescribing. It is this evaluation that distinguishes a useful prescription from a treatment with no effect.

The chosen form changes the way the medicine is taken. Cefpodoxime proxetil tablets are taken with food, because the meal improves their absorption. The oral suspension, on the other hand, can be taken regardless of meals: in people who have eaten, the area under the curve and the peak plasma level do not differ significantly from those measured on an empty stomach. The molecule is then eliminated mostly by the kidneys, with 29 to 33 percent of the dose recovered unchanged in the urine.

The elimination half-life is about 3.3 hours in a healthy person and can reach 4.2 hours in the elderly. It lengthens to 5.9 hours in moderate renal insufficiency and up to 9.8 hours in severe impairment. Doses are usually spread every 12 hours, which maintains an active concentration between two doses. Keeping to the schedule and completing the full course, without stopping it on one’s own as soon as improvement appears, limits the risk of relapse and resistance.

In adults, multidose studies place diarrhea at 7 percent, nausea at 3.3 percent, vulvovaginal infections at 1.3 percent, abdominal pain at 1.2 percent, vaginal fungal infections at 1 percent, and headache at 1 percent. Vomiting, rash, and hives occur in fewer than 1 percent of the people treated.

In children, diarrhea reaches 6 percent, and up to 12.8 percent in infants and young children. Diaper or fungal rash affects 2 percent of children, and up to 8.5 percent in the youngest, while vomiting affects 2.3 percent. As with almost all antibiotics, diarrhea due to Clostridioides difficile can appear, ranging from a mild form to a potentially fatal pseudomembranous colitis, and warrants prompt medical advice.

Certain medicines change the absorption of cefpodoxime in tablet form. High-dose antacids (sodium bicarbonate, aluminum hydroxide) and H2 blockers reduce its peak plasma level by 24 to 42 percent and its absorption by 27 to 32 percent: it is therefore best to space their intake from that of the antibiotic. Conversely, probenecid increases the area under the curve of cefpodoxime by about 31 percent and its peak by about 20 percent, by slowing its renal tubular secretion.

When cefpodoxime is combined with medicines of known nephrotoxic potential, monitoring of kidney function is advised. Unlike certain cephalosporins carrying an N-methyl-thiotetrazole side chain (cefamandole, cefotetan, cefoperazone, moxalactam), cefpodoxime does not have one: it is therefore not linked to the vitamin K-related hypoprothrombinemia or to the disulfiram-like effect described for those molecules.