allopurinol vs ampicillin/sulbactam
According to this portal's Publishing Organization, this page was last reviewed in August 2026 against our methodology. Figures and extracts on this site, including tables above 1,000 rows when the corpus is that large, are the publisher's responsibility.
Side-by-side comparison of allopurinol and ampicillin/sulbactam. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
The concurrent administration of allopurinol and ampicillin increases substantially the incidence of rashes in patients receiving both drugs as compared to patients receiving ampicillin alone. It is not known whether this potentiation of ampicillin rashes is due to allopurinol or the hyperuricemia present in these patients. There are no data with UNASYN and allopurinol administered concurrently.
Zyloprim
Unasyn
Allopurinol is a medicine that lowers uric acid levels in your body. It helps prevent gout attacks and other problems caused by high uric acid.
Unasyn is a combination of two antibiotics that fights bacteria in your body. It contains ampicillin and sulbactam.
This medicine is used to manage gout in adults. Gout causes painful attacks, joint damage, and kidney problems. Allopurinol is also used in adults and children with leukemia, lymphoma, and solid tumors who are getting cancer treatment. It helps manage high uric acid caused by the cancer treatment. It can also help adults who get calcium oxalate kidney stones often.
Unasyn treats skin infections, infections in the stomach area, and infections in women's reproductive organs. It is used when these infections are caused by certain types of bacteria. Your doctor will test to make sure Unasyn is the right medicine for your infection.
Allopurinol works by blocking an enzyme called xanthine oxidase. This enzyme helps your body make uric acid. By blocking it, allopurinol reduces the amount of uric acid in your blood and urine.
Ampicillin kills bacteria. Sulbactam helps ampicillin work better by preventing bacteria from breaking down ampicillin. Together, they stop the growth of bacteria.
- • Diarrhea
- • Nausea
- • Increased liver enzyme levels
- • Gout attacks
- • Skin rash
- • Pain at the injection site
- • Diarrhea
- • Rash
- Diarrhoea 8,423
- Fatigue 7,965
- Dyspnoea 7,658
- Nausea 7,063
- Death 6,665
- Pyrexia 71
- Pneumonia 44
- Condition Aggravated 37
- Acute Kidney Injury 29
- Rash 29
Allopurinol can cause serious skin reactions that can be deadly. Stop taking this medicine and get medical help right away if you get a skin rash or any other signs of an allergic reaction.
You should not take Unasyn if you have had a severe allergic reaction to penicillins or cephalosporins. You should also not take it if you have had liver problems caused by Unasyn in the past.
Allopurinol may harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not recommended to breastfeed while taking this medicine because it can pass into breast milk.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if Unasyn will harm your unborn baby. Talk to your doctor about the risks and benefits of taking Unasyn while breastfeeding.
Also Compare, Nearby Drugs
Compare allopurinol with
Compare ampicillin/sulbactam with
How to Read This allopurinol vs ampicillin/sulbactam Comparison
allopurinol is classified in the Xanthine Oxidase Inhibitor drug class, while ampicillin/sulbactam sits within the Penicillin / Beta-Lactamase Inhibitor class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, allopurinol has 37,774 submissions while ampicillin/sulbactam has 210. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to taking these two medicines at the same time significantly increases your chances of developing a skin rash.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for allopurinol or ampicillin/sulbactam.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.