Paromomycin Drug Interactions: What to Avoid and What to Tell Your Doctor

Because paromomycin is poorly absorbed from the gastrointestinal tract under normal conditions, many of its potential drug interactions only matter if it reaches the bloodstream. But some interactions can occur even at the intestinal level, and others are clinically significant in patients who may absorb more drug than usual (for example, those with ulcerative bowel lesions). Here's what to know and what to tell your prescriber.

Interactions to Avoid (Major Risk)

These combinations should generally be avoided, or used only with close medical supervision:

Loop diuretics (furosemide, bumetanide, ethacrynic acid): Both aminoglycosides and loop diuretics are independently ototoxic and nephrotoxic. Combined use significantly increases the risk of permanent hearing damage and kidney injury. Avoid this combination if at all possible.

Neuromuscular blocking agents (atracurium, vecuronium, succinylcholine, etc.): Paromomycin can enhance the effects of neuromuscular blockers if absorbed, creating a synergistic risk of prolonged apnea (inability to breathe). This is most relevant in perioperative settings. Notify your anesthesiologist if you are taking paromomycin and undergoing surgery.

BCG vaccine (live bacterial vaccine): Paromomycin can kill the live bacteria in BCG vaccine, rendering it ineffective. The BCG vaccine should not be administered while a patient is taking paromomycin. Wait until the antibiotic course is completed before receiving BCG.

Other aminoglycoside antibiotics (gentamicin, tobramycin, amikacin, neomycin): Concurrent use of two aminoglycosides significantly increases the risk of nephrotoxicity and ototoxicity. Avoid combination therapy.

Moderate Interactions (Use With Caution, Monitor)

Warfarin (blood thinner): Paromomycin may cause a small increase in the anticoagulant effect of warfarin by reducing gut bacteria that produce vitamin K. If you take warfarin, your INR should be monitored more closely during and after paromomycin treatment.

Oral contraceptives: Paromomycin can alter intestinal flora and may slightly reduce the absorption of oral hormonal contraceptives. The risk of contraceptive failure is considered low, but using a backup method during treatment is a reasonable precaution — discuss with your prescriber.

Oral methotrexate: Paromomycin may reduce the GI absorption of oral methotrexate by killing bacteria involved in enterohepatic circulation. If you take oral methotrexate, inform your rheumatologist or oncologist before starting paromomycin.

Voclosporin (calcineurin inhibitor): Concurrent use of voclosporin and aminoglycosides may increase the risk of nephrotoxicity. Monitor kidney function if this combination is necessary.

Zoledronic acid and other nephrotoxic drugs: If absorbed, paromomycin combined with other nephrotoxic agents (NSAIDs, contrast agents, cisplatin) may increase kidney risk.

Loratadine (Claritin): Loratadine may increase paromomycin levels via P-glycoprotein (MDR1) efflux transporter inhibition. Monitor for increased paromomycin effects if this combination is used.

What to Tell Your Doctor Before Starting Paromomycin

Before starting paromomycin, tell your prescriber about:

All prescription medications, including blood thinners, diuretics, immunosuppressants, and antibiotics

All OTC medications, vitamins, and herbal supplements

Any history of kidney disease or hearing problems

Any history of intestinal ulcers or inflammatory bowel disease (increases absorption risk)

If you are pregnant, planning to become pregnant, or breastfeeding

If you have any scheduled surgeries (anesthesiologists need to know about aminoglycoside use)

Note on Contraindications

Paromomycin is contraindicated (should not be used) in patients with a known hypersensitivity to paromomycin or other aminoglycosides, and in those with intestinal obstruction. Patients with bowel obstruction cannot pass the drug through the gut, which increases the risk of absorption and toxicity.

See also: Paromomycin Side Effects and What Is Paromomycin? for additional patient information.