Antibiotics in elderly patients — special considerations

This article provides information about antibiotic use in older adults. Always follow your elder's doctor's instructions regarding antibiotic therapy and report any side effects immediately.

There's a mistaken belief that infections in older adults are minor inconveniences to be treated like anyone else would treat them. But your 82-year-old parent who develops a urinary tract infection isn't experiencing the same illness as a 35-year-old with the same infection. The consequences are different. The body's response is different. Even the antibiotics themselves work differently in older bodies.

Infections hit harder in older adults for several reasons. The immune system weakens with age. The kidneys don't filter as well. The liver processes drugs differently. What might be a straightforward infection in a younger person can become life-threatening in an older one. A simple urinary tract infection can trigger confusion and falls. Pneumonia can deteriorate rapidly. A wound infection can spread to the bloodstream. This is why antibiotics in older adults require careful selection and monitoring.

When a doctor prescribes an antibiotic for your elder, they're making several complex decisions simultaneously. Which antibiotic will work against this particular infection? Will this antibiotic harm their kidneys? Will it interact with the ten other medications they're taking? Is the dosage appropriate for someone with decreased kidney function? What are the likely side effects and how serious might they be?

Kidney function is the central issue for antibiotic selection in older adults. Many antibiotics are cleared from the body through the kidneys. If kidney function is reduced—and it often is in older age, even if the bloodwork looks relatively normal—the antibiotic accumulates in the body. Too much accumulation becomes toxic. This is why many antibiotics are dosed differently in older adults than in younger people. It's also why kidney function is tested before antibiotics are started.

If your elder has chronic kidney disease or their kidney function recently changed, make sure the prescribing doctor knows. Sometimes doctors prescribe standard doses without realizing kidney function is reduced. This is where you might need to speak up. If you know your parent's kidney function is declining, mention it when an antibiotic is prescribed.

The side effects of antibiotics in older adults can be particularly troublesome. Fluoroquinolones, a common class of antibiotics, can cause tendon rupture, which might manifest as suddenly being unable to walk without explanation. They can cause serious neurological problems. Yet these antibiotics are still prescribed because for certain infections, they're the right choice. The decision isn't about avoiding them entirely but about using them appropriately.

The most feared complication of antibiotics in older adults is Clostridioides difficile infection. This happens when antibiotics kill the good bacteria in the gut along with the bad bacteria causing the original infection. Without the protective bacteria, a pathogenic organism called C. difficile overgrows and causes severe diarrhea, which can be life-threatening. Anyone on antibiotics should be watched carefully for severe diarrhea, especially older adults. If this develops, it must be reported immediately.

Supporting someone through an antibiotic course means understanding what to monitor. Older adults need encouragement to actually take the full course of antibiotics. Some feel better after a few days and stop taking the medication. This creates antibiotic resistance and can allow the infection to return. Others have trouble remembering to take medication on the prescribed schedule, especially if they're taking it three or four times daily.

Practical strategies help. You might set phone reminders for their medication times. You might prepare a pill organizer with all their antibiotics and other daily medications premeasured. Some pharmacies will create compliance packs that organize daily doses. For someone who's already confused or overwhelmed, these systems reduce the chance of missing doses or taking doses twice.

The interaction between antibiotics and other medications is significant. Antibiotics can affect how blood thinners work, how diabetes medications work, how many other drugs are metabolized. When your elder is prescribed an antibiotic, the doctor should review their other medications. But sometimes this doesn't happen thoroughly. If you know they're on important medications, mention them when the antibiotic is being prescribed. "My mother takes warfarin" or "My father is on metformin" provides important information.

Some antibiotics are hard on the stomach, especially if taken without food. Others must be taken on an empty stomach for proper absorption. Some cannot be taken near calcium or iron supplements. The prescription should come with clear instructions about these details. If it doesn't, ask the pharmacist. If the instructions are confusing, ask for clarification before your parent leaves the pharmacy.

Supporting recovery means watching for improvement and complications equally. Your elder should start feeling better within a day or two of starting most antibiotics. If they feel worse, or if new symptoms develop, contact their doctor. If fever spikes instead of improving, that's a problem. If diarrhea develops,especially severe diarrhea,that needs immediate attention.

The amount of fluids they drink matters too. Being well-hydrated helps the body clear the infection and helps the kidneys process the antibiotic safely. Encourage water, soup, herbal tea, and other fluids throughout the day.

Sometimes doctors need to switch antibiotics because the first choice isn't working, side effects are intolerable, or lab results show the infection requires a different antibiotic. This isn't a failure. Infections sometimes require adjustments to treatment. What matters is that the doctor is monitoring progress and willing to make changes.

After the antibiotic course ends, probiotics sometimes help restore the good bacteria in the gut. If your elder takes probiotics, they shouldn't take them at the same time as the antibiotic,the antibiotic will kill the bacteria in the probiotic. Starting them after the course ends makes more sense.

The broader context matters too. Sometimes an infection signals another problem. A urinary tract infection might mean your elder isn't drinking enough or can't empty their bladder completely. Recurrent infections might suggest something needs investigation. After treating the acute infection, the conversation might shift to preventing future infections.

Your role in supporting antibiotic therapy is practical and observational. You ensure your elder actually takes the medication as prescribed. You watch for both improvement and complications. You communicate clearly with their doctor about other medications, previous reactions, and any concerning symptoms. You help them stay hydrated. You arrange the medication in a way they can remember to take it. These practical steps increase the chance that the antibiotic works well and the infection resolves without complications.

Report immediately to your elder's doctor if they develop severe diarrhea, severe allergic reaction, difficulty breathing, severe dizziness, or symptoms of the original infection worsening despite antibiotics. Never stop antibiotics early without medical guidance, even if your elder feels better.