Compare penicillin vs. Bactrim

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

Treats bacterial infections.

Penicillin VK (penicillin) is good at treating strep throat and is cheap, however, it can only be used for certain infections as many bacteria have developed resistance to it.

3.9/ 5 average rating with 1297 reviewsforpenicillin
Kills bacteria.

Bactrim (sulfamethoxazole / trimethoprim) is good for treating many bacterial infections and is available as a generic. However, you can be more likely to sunburn.

3.6/ 5 average rating with 473 reviewsforBactrim
  • Compared to alternatives, Penicillin VK (penicillin) is the preferred choice for treating strep throat infections.
  • This medicine is available as a generic, which is cheap.
  • It’s also available in different forms: pill and liquid.
  • Widely available as a generic product and in a variety of formulations (tablet, capsule, suspension).
  • Works well to treat many types of bacterial infections
  • Many bacteria are resistant to Penicillin VK (penicillin), so it only works for certain infection typically in ear, nose, and throat.
  • Penicillin VK (penicillin) has a bitter taste. Children might not like the taste.
  • Makes you sensitive to the sun.
  • Can upset your stomach
  • Drink plenty of water or fluids to avoid harming your kidneys
  • May cause birth defects
Used for
Dosage forms
  • Pill
  • Liquid
  • Pill
  • Liquid
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1297 reviews so far
saidit'sworth it
saiditworked well
saidit'sa big hassle

Have you used Penicillin VK (penicillin)?

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473 reviews so far
saidit'sworth it
saiditworked well
saidit'sa big hassle

Have you used Bactrim (sulfamethoxazole / trimethoprim)?

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Side effects
The Penicillin VK (penicillin) FDA package insert doesn’t have numbers about how common side effects are.
The Bactrim (sulfamethoxazole / trimethoprim) FDA package insert doesn’t have numbers about how common side effects are.
Risks and risk factors
  • Diarrhea
    • Taking Penicillin VK (penicillin) for a long time
  • Interaction with birth control pills
  • Allergic reaction
    • History of severe allergic reaction to Penicillin VK (penicillin)
    • Cephalosporin medication allergy
See more detailed risks and warnings
  • Diarrhea
  • Sunburn
  • Rash
  • Harm to fetus
  • Lower kidney function
    • Elderly
    • Taking other medicines that lower kidney function
See more detailed risks and warnings