Paromomycin Side Effects: What to Expect and When to Call Your Doctor

Paromomycin (Humatin) is generally well tolerated when used as directed. Because it's barely absorbed from the gastrointestinal tract — nearly 100% is recovered in the stool — most patients experience only mild GI side effects during treatment. However, there are serious risks if the drug is used incorrectly or in patients with certain conditions.

Common Side Effects of Paromomycin

The most common side effects are gastrointestinal and typically appear at higher doses (above 3 g per day):

Nausea — most common; taking the medication with a meal can help

Abdominal cramps — often mild to moderate during treatment

Diarrhea — may occur especially at doses over 3 g/day

Heartburn or vomiting — less common but reported

These effects are usually mild and resolve once the course of treatment is completed. Always take paromomycin with food as directed by your prescriber.

Serious Side Effects — When to Call Your Doctor Immediately

Although paromomycin is poorly absorbed from the gut under normal circumstances, if you have ulcerative lesions (sores) in your intestines, more drug can enter your bloodstream. This raises the risk of the same serious toxicities seen with other aminoglycoside antibiotics:

Nephrotoxicity (kidney damage): Signs include decreased urination, swelling in the legs or feet, unusual fatigue, or confusion. Call your doctor right away if you notice these symptoms.

Ototoxicity (hearing or balance damage): Signs include ringing in the ears (tinnitus), hearing loss, or dizziness/vertigo. These can sometimes be permanent. Report them to your prescriber immediately.

Neuromuscular blockade (rare): In rare cases (especially if absorbed systemically), aminoglycosides can impair muscle function. Seek emergency care if you notice sudden muscle weakness or breathing difficulty.

Superinfection: Like any antibiotic, paromomycin can allow non-susceptible organisms (including fungi) to overgrow. Signs include new or worsening symptoms during or after treatment. Contact your prescriber.

Allergic reaction: Rare but possible. Signs of a serious allergic reaction include hives, difficulty breathing, or swelling of the face/tongue. Call 911 or go to the ER immediately.

Who Is at Higher Risk for Serious Side Effects?

Most patients taking paromomycin at standard doses for a short course have minimal systemic exposure and are unlikely to experience serious side effects. Your risk is higher if:

You have ulcerative bowel disease or active intestinal lesions (which increase absorption)

You already have kidney problems (reduces drug clearance if absorbed)

You are taking other nephrotoxic or ototoxic drugs at the same time (see our drug interactions guide)

You are prescribed very high doses or a long treatment course

Tips for Reducing Side Effects

Always take paromomycin with meals to reduce GI upset

Take the full prescribed course — do not stop early, even if you feel better

Tell your prescriber about all other medications you take, including OTC drugs and supplements

Avoid loop diuretics (like furosemide or bumetanide) during paromomycin treatment if possible — they increase the risk of ototoxicity

Related Resources

See also: Paromomycin Drug Interactions and What Is Paromomycin? for more patient-friendly information.