How Itraconazole Is Used to Treat Fungal Infections in Older Adults

When an older adult develops a fungal infection, it’s not just a skin rash or a nagging nail issue-it can become a serious health threat. Fungi thrive in warm, moist areas, and as people age, their immune systems slow down, their skin thins, and they’re more likely to have conditions like diabetes or poor circulation. That’s why fungal infections in the elderly are more common, harder to treat, and often get worse before they’re properly diagnosed. One of the most effective oral antifungal drugs used in this group is itraconazole. But using it isn’t as simple as popping a pill. It requires careful dosing, monitoring, and understanding of how it interacts with other medications and the aging body.

Why fungal infections are more dangerous in older adults

Fungal infections like onychomycosis (nail fungus), tinea pedis (athlete’s foot), and candidiasis aren’t just annoying-they can lead to skin breaks, secondary bacterial infections, and even hospitalization in seniors. A 2023 study in the Journal of the American Geriatrics Society found that over 30% of adults over 70 have some form of fungal nail infection, and nearly half of them never seek treatment because they think it’s ‘just aging.’ But untreated fungal infections in older people often spread, cause pain when walking, and increase fall risk. In those with diabetes or vascular disease, even a small fungal sore can turn into a foot ulcer that doesn’t heal.

Also, older adults are more likely to be on multiple medications, live in long-term care facilities, or wear dentures-each of which creates a perfect environment for fungi to grow. Candida albicans, the most common yeast causing oral thrush, is found in up to 40% of nursing home residents. And because their immune systems don’t respond as quickly, these infections don’t clear up on their own like they might in younger people.

How itraconazole works against fungi

Itraconazole is an azole antifungal, which means it blocks the production of ergosterol-a key building block in fungal cell membranes. Without ergosterol, the fungal cell wall becomes weak and leaks, killing the organism. Unlike older antifungals like griseofulvin, itraconazole works against a wide range of fungi: dermatophytes (which cause skin and nail infections), yeasts like Candida, and even some molds.

It’s especially useful for deep or stubborn infections. For example, if someone has fungal pneumonia caused by Aspergillus, or a severe nail infection that hasn’t responded to topical creams, itraconazole is often the go-to oral option. It also stays in the body longer than fluconazole, meaning it can be taken less frequently-sometimes just once a day, or even in pulse dosing (a week on, three weeks off), which helps reduce side effects.

Dosing and administration in elderly patients

Dosing itraconazole for older adults isn’t one-size-fits-all. The standard adult dose for nail fungus is 200 mg once daily for 3 months, but for someone over 70 with kidney or liver issues, that might be too much. The liver breaks down itraconazole, and many elderly patients have reduced liver function. The kidneys help clear the drug, and kidney function naturally declines with age.

Doctors often start low: 100 mg per day, or even alternate-day dosing, especially if the patient is on other meds. For oral thrush, a 7-14 day course at 100-200 mg daily is typical. For nail infections, pulse dosing is common: 200 mg twice daily for one week, then no drug for three weeks, repeated for three cycles. This reduces total drug exposure and lowers the chance of liver damage.

It’s also important to take itraconazole with food-preferably a full meal-or with an acidic drink like cola. The drug doesn’t absorb well on an empty stomach, and many elderly people take it with water and a biscuit, which isn’t enough. Without proper absorption, the treatment fails.

Key drug interactions to watch for

This is where itraconazole gets tricky in older adults. Most seniors take at least three to five medications daily-statins for cholesterol, blood pressure pills, diabetes drugs, or pain relievers. Itraconazole is a strong inhibitor of the CYP3A4 liver enzyme, which metabolizes many of these drugs. That means levels of those other drugs can build up to dangerous levels.

For example:

• Combining itraconazole with simvastatin or lovastatin can cause severe muscle damage (rhabdomyolysis).
• It can raise levels of calcium channel blockers like amlodipine, leading to dangerously low blood pressure.
• It increases the risk of irregular heart rhythms when taken with certain antiarrhythmics or antidepressants like amitriptyline.
• It can interfere with blood thinners like warfarin, requiring frequent INR checks.

Before prescribing itraconazole, pharmacists and doctors must review the patient’s full medication list. Many GP practices now use automated alerts in their electronic health records to flag these interactions. If a safer alternative isn’t available, the dose of the interacting drug may need to be lowered, or the patient monitored closely with blood tests.

Safety and side effects in older patients

Itraconazole is generally well tolerated, but side effects are more common-and more serious-in the elderly. The most frequent are nausea, bloating, and headaches. But the real concern is liver toxicity. About 1 in 100 patients develop elevated liver enzymes, and in rare cases, this leads to liver failure. For patients over 70, doctors typically check liver function tests before starting treatment, then again at 4 and 8 weeks.

Heart problems are another risk. Itraconazole can cause fluid retention and, in rare cases, worsen heart failure. Anyone with a history of congestive heart failure should avoid it. If an older patient starts gaining weight quickly, swelling in the ankles, or feeling unusually short of breath, they should stop the drug and call their doctor immediately.

Also, itraconazole can lower potassium levels, which can be dangerous if the patient is already on diuretics. Regular blood tests for electrolytes are often needed during treatment.

When not to use itraconazole

There are clear red flags where itraconazole should be avoided:

• Known allergy to azole antifungals
• Active liver disease or unexplained high liver enzymes
• Severe heart failure (NYHA Class III or IV)
• Use with certain medications like quinidine, dofetilide, or cisapride (which can cause fatal heart rhythms)
• Pregnancy (though this is rarely relevant in the elderly)

For patients who can’t take itraconazole, alternatives include terbinafine (for nail fungus), fluconazole (for yeast infections), or topical treatments like ciclopirox nail lacquer. But oral treatment is often necessary when the infection is widespread or has penetrated deep into the nail bed or skin.

Monitoring and follow-up

Treatment doesn’t end when the pills are finished. Fungal nail infections can take 6 to 12 months to fully grow out. Even after the infection is gone, the nail may still look damaged. Patients need to know this so they don’t think the treatment failed.

Follow-up should include:

1. Liver function tests at 4 and 8 weeks
2. Electrolyte check if on diuretics
3. Review of other medications for interactions
4. Assessment of symptom improvement
5. Discussion of hygiene practices: drying feet thoroughly, changing socks daily, avoiding shared showers

Many older adults forget to take their pills. A pill organizer, family member reminders, or a home care nurse can make a big difference. Studies show adherence improves by over 60% when patients have a simple system in place.

Real-world outcomes and patient stories

In a 2024 observational study of 187 patients over 70 treated with itraconazole for toenail fungus, 68% had complete or near-complete clearance after 12 months. But only 52% completed the full course-many stopped because of side effects or because they thought it wasn’t working. Those who stayed on treatment had far fewer recurrences.

One patient, 78-year-old Margaret from Leeds, had fungal nails for over 10 years. She couldn’t wear closed shoes without pain. After starting itraconazole with weekly liver tests and a pill box, her nails cleared by month 8. She still takes a foot soak daily and changes her socks twice a day. ‘I thought it was just part of getting old,’ she says. ‘Now I walk without pain. That’s worth the pills.’

Alternatives and when to consider them

Not everyone can or should take itraconazole. Terbinafine is often preferred for nail fungus because it has fewer drug interactions and a lower risk of liver issues. It’s taken daily for 6 weeks for fingernails and 12 weeks for toenails. But it’s not as effective against yeast infections.

Fluconazole is good for candidiasis and can be taken weekly, but it doesn’t work well on dermatophytes. Topical treatments like efinaconazole or tavaborole are safe but require daily application for up to a year-hard for someone with arthritis or poor eyesight.

For very frail patients or those with multiple contraindications, laser therapy or nail removal may be considered, though evidence is limited. The goal isn’t always to cure-it’s to reduce pain, prevent spread, and improve quality of life.

What caregivers and family members should know

If you’re helping an older relative manage a fungal infection, here’s what matters:

• Don’t assume it’s ‘just a fungus’-get it checked by a doctor.
• Keep a list of all medications and supplements they take.
• Help them take the pill with food and an acidic drink.
• Watch for swelling, shortness of breath, or yellowing skin.
• Don’t stop the medicine early, even if the nail looks better.
• Encourage foot hygiene: dry between toes, avoid walking barefoot in communal areas.

Small actions make a big difference. A clean, dry pair of socks isn’t glamorous-but it prevents reinfection.

Final thoughts

Itraconazole is a powerful tool for treating stubborn fungal infections in older adults. But it’s not a magic bullet. It works best when used carefully-dosed according to kidney and liver function, checked for drug interactions, and paired with good hygiene and follow-up. For many elderly patients, it means regaining mobility, comfort, and confidence. But without proper oversight, it can do more harm than good.

The key isn’t just prescribing the drug-it’s managing the whole person. That means listening, monitoring, and adapting treatment to fit their life, not the other way around.