Amphotericin B for Macaws: Uses, Dosing & Side Effects

This information is for educational purposes only. Never give your pet any medication without your veterinarian's guidance. Dosing, frequency, and safety depend on your pet's specific health profile.

Amphotericin B is a prescription antifungal medication used in veterinary medicine for serious fungal infections. It belongs to the polyene class and works by binding to ergosterol in fungal cell membranes, which damages the fungus and can kill it. In birds, your vet may use it as a nebulized medication, by intratracheal administration, or in selected cases by intravenous infusion.

In macaws, amphotericin B is most often discussed in the context of aspergillosis, a fungal disease that can affect the air sacs, lungs, and other tissues. Because this drug can also affect the kidneys and electrolyte balance, it is not a medication pet parents should ever dose on their own. Careful route selection, hydration support, and follow-up monitoring are a big part of safe use.

Some avian cases are treated with conventional amphotericin B, while others may be managed with lipid-based formulations in referral settings. Those advanced formulations are often considered when your vet is trying to reduce kidney stress or treat a more severe systemic infection.

In macaws, amphotericin B is primarily used for fungal infections of the respiratory tract, especially aspergillosis. This matters because parrots can hide illness until disease is advanced, and fungal infections may cause vague signs at first, such as reduced activity, voice change, weight loss, or increased breathing effort.

Your vet may consider amphotericin B when a fungal infection is severe, when rapid antifungal action is needed, or when local airway treatment is helpful. In birds, published avian dosing references include nebulized and intratracheal use for respiratory disease, and short-course intravenous use has also been described.

It is not the only option. Depending on the location and severity of infection, your vet may pair amphotericin B with other antifungals such as itraconazole, voriconazole, terbinafine, or topical airway therapy. The best plan depends on your macaw's species, liver and kidney status, appetite, stress tolerance, and whether the infection appears localized or systemic.

Amphotericin B dosing in birds is route-specific and should be set by your vet. Merck Veterinary Manual avian references list respiratory therapy doses such as nebulization at 1 mg/mL in sterile water or saline for about 15 minutes every 6 to 12 hours, intratracheal dosing at 1 mg/kg every 8 to 12 hours, and another bird reference of 1 mg/kg nebulized over 15 minutes every 24 hours for 10 to 14 days. A separate Merck table also lists 1.5 mg/kg IV every 8 hours for 3 to 5 days in birds.

Those numbers are not interchangeable. A macaw being treated by nebulization is not dosed the same way as a bird receiving intratracheal or IV therapy. Your vet may also adjust the plan based on body weight, hydration, kidney values, severity of breathing signs, and whether other antifungals are being used at the same time.

Because amphotericin B can be hard on the kidneys, monitoring often matters as much as the dose itself. Your vet may recommend repeat weight checks, hydration assessment, bloodwork, and review of droppings, appetite, and breathing effort during treatment. If your macaw seems weaker, drinks less, eats less, or shows worsening respiratory distress, contact your vet promptly.

The biggest safety concern with amphotericin B is kidney injury. In practice, that means your vet may watch closely for dehydration, rising kidney values, reduced urate output, weakness, or changes in drinking and appetite. Electrolyte problems, including low potassium, can also occur and may contribute to weakness or poor recovery.

Macaws may also show more general medication-related signs such as reduced appetite, lethargy, stress with handling, or worsening tolerance of treatment sessions. With nebulized therapy, some birds become anxious during restraint or chamber treatment, and birds with severe breathing compromise may not tolerate prolonged sessions well.

See your vet immediately if your macaw has open-mouth breathing, marked tail bobbing, collapse, severe weakness, stops eating, or seems dramatically less responsive. Those signs may reflect progression of the fungal disease, medication intolerance, dehydration, or another urgent complication.

Amphotericin B deserves extra caution when used with other medications that can stress the kidneys. Merck notes increased nephrotoxicity risk when amphotericin B is combined with aminoglycosides, and aminoglycoside references also warn about added kidney risk when nephrotoxic or nephroactive drugs are used together. In practical terms, your vet may be especially careful if your macaw is also receiving drugs such as gentamicin, amikacin, certain NSAIDs, or diuretics.

Electrolyte shifts can also matter. Drugs that contribute to dehydration, azotemia, or potassium loss may increase the chance of treatment complications. If your macaw is on multiple medications, supplements, or compounded therapies, bring a full list to your appointment, including anything added to food or water.

Combination antifungal therapy is sometimes intentional in avian medicine, but it should be planned, not improvised. Your vet may combine amphotericin B with another antifungal to target a difficult infection, while still adjusting monitoring to reduce kidney and hydration risks.