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Ivermectin vs. Metronidazole

Head-to-head comparisons of medication uses, side effects, warnings, and more.

Key takeaways

Ivermectin (Stromectol) and metronidazole (Flagyl) are both used to treat parasitic infections, but they belong to different medication classes. Ivermectin is an antiparasitic agent, while metronidazole is a nitroimidazole antibiotic. Ivermectin is FDA-approved for treating strongyloidiasis and river blindness, and it is sometimes used off-label for scabies. Metronidazole is used for a variety of bacterial and parasitic infections, including trichomoniasis and amebiasis. Ivermectin is typically taken as a single dose based on body weight, whereas metronidazole is usually taken multiple times a day for several days. Both medications are available as lower-cost generics. Common side effects of ivermectin include stomach pain and nausea, while metronidazole can cause headaches and a metallic taste. Both medications can interact with warfarin, and metronidazole should not be taken with alcohol or disulfiram due to serious interactions.

Ivermectin

(Stromectol)

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Metronidazole

(Flagyl)

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Summary for Ivermectin

Prescription only

Ivermectin (Stromectol) is an antiparasitic medication. It's used to treat infections caused by certain parasites in the tropical areas. Ivermectin (Stromectol) is also sometimes prescribed off-label for treating scabies. Ivermectin (Stromectol) can be taken by adults and children weighing 15 kg and more. Depending on what infection you have, you might only need a single dose of ivermectin (Stromectol), or repeated treatments. Some common side effects of ivermectin (Stromectol) include stomach pain and nausea. Watch out for dizziness, itching, rash, and swelling, which can be symptoms of a severe allergic reaction.

Indications for Ivermectin

  • Treatment of a parasitic gut infection caused by Strongyloides stercoralis (Strongyloidiasis)
  • Treatment of parasitic skin and eye infections caused by Onchocerca volvulus (Onchocerciasis, or river blindness)

Pros and Cons for Ivermectin

Pros

  • Available as a lower-cost generic medication
  • Only requires one dose of treatment for strongyloidiasis
  • Treatment of choice for river blindness

Cons

  • Requires repeated stool tests to make sure your stomach infection is completely cleared
  • Must be taken on an empty stomach
  • Not a safe choice during pregnancy

Common Side Effects for Ivermectin

Reported by people treated for strongyloidiasis

  • Dizziness (3%)
  • Itching (3%)
  • Nausea (2%)
  • Diarrhea (2%)

Reported by people treated for river blindness

  • Itching (28%)
  • Fever (23%)
  • Skin swelling or rash (23%)
  • Swollen lymph nodes (5-13%)
  • Joint pain (9%)

Warnings for Ivermectin

  • Severe allergic reaction (Mazzotti reaction)
  • Brain and nervous system problems

Summary for Metronidazole

Prescription only

Metronidazole (Flagyl) is an oral antibiotic for adults and children. It's used to treat certain bacterial and parasitic infections, including bacterial vaginosis (a type of vaginal bacteria infection) and trichomoniasis (a sexually transmitted infection, or STI). Metronidazole (Flagyl) is taken by mouth, typically 3 times a day. Some common side effects of this medication include diarrhea, nausea, and vomiting. Avoid drinking alcohol while taking and for 3 days after stopping metronidazole (Flagyl) because this combination can cause a serious reaction. Metronidazole (Flagyl) is available as a lower-cost generic.

Indications for Metronidazole

Treatment of certain bacterial and parasitic infections, including:

Pros and Cons for Metronidazole

Pros

  • Taken by mouth
  • Available as a lower-cost generic medication
  • Can be used to treat different types of bacterial infection
  • Immediate-release formulations can be taken with or without food

Cons

Common Side Effects for Metronidazole

Please note: These are common side effects reported by people who took extended-release metronidazole (Flagyl)

  • Headache (18%)
  • Inflammation of the vagina (15%)
  • Nausea (10%)
  • Metallic taste (9%)
  • Flu-like symptoms (6%)

Warnings for Metronidazole

  • Possible risk of cancer
  • Serious allergic reactions
  • Brain and nerve problems
  • Liver and kidney problems
  • Risk of fungal infection
  • Risk of drug resistance
  • Lower white blood cell counts
  • Interaction with other medications

Prices with our coupons for Ivermectin vs. Metronidazole

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Ivermectin20 tablets / 3mg
$27.75$68.89
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Metronidazole14 tablets / 500mg
$10.73$14.99
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