Compare Penicillin vs. Bactrim

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

Penicillin Vk
(Penicillin)

Bactrim
(Sulfamethoxazole / Trimethoprim)

Kills bacteria. Penicillin Vk (Penicillin) is good for treating many bacterial infections and is available as a generic. You may need to use another form of birth control along with your birth control pills. It's also best taken on an empty stomach but it can cause an upset stomach.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. Also, it can cause birth defects, so talk to your doctor if you're pregnant.
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Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.276021588280647Penicillin
Reviews for Penicillin Vk (Penicillin)
71%
of people (All ages) say Penicillin Vk (Penicillin) is worth it
52%
say it works well
12%
say it's a big hassle
1297 reviews
Have you used Penicillin Vk (Penicillin)?
Worth itNot sureNot worth it
Reviews for Bactrim (Sulfamethoxazole / Trimethoprim)
59%
12% vs. Penicillin Vk (Penicillin)
50%
2% vs. Penicillin Vk (Penicillin)
22%
10% vs. Penicillin Vk (Penicillin)
470 reviews
Have you used Bactrim (Sulfamethoxazole / Trimethoprim)?
Worth itNot sureNot worth it
Side effects
PenicillinBactrim

The Penicillin FDA package insert doesn’t have numbers about how common side effects are.

More about Penicillin side effects »

The Bactrim FDA package insert doesn’t have numbers about how common side effects are.

More about Bactrim side effects »
How it works
PenicillinBactrim
Penicillin Vk (Penicillin) is an antibiotic. It kills bacteria by preventing them from making their own protective covering.Bactrim (Sulfamethoxazole / Trimethoprim) is a combination antibiotic that contains sulfamethoxazole and trimethoprim. It kills bacteria by preventing them from making proteins and other chemicals that keep them alive.
Type of medication
PenicillinBactrim
Antibiotic
Penicillin
Prescription only
Antibiotic
Sulfonamide
Prescription only
Available as
PenicillinBactrim
  • Pill
  • Pill
  • Liquid
Used for (click to learn more)
PenicillinBactrim
Risk factors for serious side effects
PenicillinBactrim
      • Prior severe allergic reaction to Penicillin Vk (Penicillin)
      Detailed Penicillin Vk (Penicillin) risks & warnings »
              Detailed Bactrim (Sulfamethoxazole / Trimethoprim) risks & warnings »
              Pregnancy category
              PenicillinBactrim
              NFDA pregnancy category (Unknown)

              The FDA hasn’t classified this medicine’s effects on unborn babies. Talk with your doctor about this medicine if you’re pregnant or planning on it.

              See the FDA package insert
              DFDA pregnancy category (Weigh risks vs. benefits)

              Research studies with real people found harmful effects on unborn babies, but the benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

              See the FDA package insert
              Food
              • Try to take it on an empty stomach. If this gives you an upset stomach, take it with food.
              No specific food related info.
              Upsides and benefits
              PenicillinBactrim
              • Available in generic.
              • Available in different forms: tablet, capsule and suspension.
              • Used to treat many types of bacterial infections.
              • Less resistance seen to this antibiotic. Your doctor may run tests to see if Bactrim responds to your infection.
              • Available in generic.
              • Available in different forms: tablet, capsule and suspension.
              • Used to treat many types of bacterial infections.
              Downsides and risks
              PenicillinBactrim
              • Many bacteria have developed resistance. Your doctor may run tests to see if Penicillin will work on your infection.
              • Can make birth control pills less effective.
              • Best taken on an empty stomach, but can cause stomach upset and diarrhea.
              • Makes your skin more sensitive to the sun.
              • Has to be taken with plenty of liquids.
              • May cause birth defects.
              • Can cause diarrhea.
              Tips from our pharmacists for people taking the medication
              PenicillinBactrim
              • If you're taking birth control pills, this medication can make them less effective.
              • Try to take it on an empty stomach. If this gives you an upset stomach, take it with food.
              • Take this medication exactly how your doctor tells you to.
              • Can cause diarrhea, nausea or vomiting.
              • Can make your skin more sensitive to the sun.
              • Drink plenty of liquids when taking the medication.
              • Can cause rash.
              • Take this medication exactly how your doctor tells you to.
              • Can cause diarrhea, nausea or vomiting.
              Learn more
              More about PenicillinSide effectsReviews & ratingsAlternativesFDA package insert
              Have you used Penicillin Vk (Penicillin)?
              Worth itNot sureNot worth it
              More about BactrimSide effectsReviews & ratingsAlternativesFDA package insert
              Have you used Bactrim (Sulfamethoxazole / Trimethoprim)?
              Worth itNot sureNot worth it