Two medicines, side by side
Allopurinol vs amoxicillin
Allopurinol is labeled for gout; amoxicillin for bacterial infections and acid reflux and ulcers. Their labels share no use, so they are not alternatives to each other. Drugs@FDA records approvals of allopurinol since 1966 and of amoxicillin since 1974. Pharmacies paid $0.0315 per allopurinol 100 mg tablet and $0.0788 per amoxicillin 500 mg capsule (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, allopurinol is a xanthine oxidase inhibitor and amoxicillin a penicillin-class antibacterial.
Check it at the source: the allopurinol FDA label on DailyMed (effective May 21, 2026); the amoxicillin FDA label on DailyMed (effective February 22, 2024).
Highlights of the allopurinol record
Allopurinol (Zyloprim) · label of May 21, 2026
Used for
From the label: indicationsAllopurinol tablet is indicated for: The management of adults with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy) The management of adult and pediatric patients with leukemia, lymphoma and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels The management of adult […]
On the market
- Earliest approval on file
- August 19, 1966
- Generic labelers
- 44 labelers
- Pharmacy cost
- $0.0315 per tablet
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 6
Highlights of the amoxicillin record
Amoxicillin (Amoxil) · label of February 22, 2024
Used for
From the label: indicationsAdults and Pediatric Patients • Upper Respiratory Tract Infections of the Ear, Nose, and Throat Amoxicillin is indicated in the treatment of infections due to susceptible (ONLY β-lactamase–negative) isolates of Streptococcus species. (α- and β-hemolytic isolates only), Streptococcus pneumoniae, Staphylococcus spp. , or Haemophilus influenzae. […]
On the market
- Earliest approval on file
- January 18, 1974
- Generic labelers
- 38 labelers
- Pharmacy cost
- $0.0788 per capsule
Supply and safety
- Shortage
- No current entry
- Recalls
- 12
Source: FDA drug labels via openFDA (Allopurinol label of May 21, 2026, Amoxicillin label of February 22, 2024); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do allopurinol and amoxicillin differ on the record?
In FDA's classes, allopurinol is a xanthine oxidase inhibitor and amoxicillin a penicillin-class antibacterial.
How each works, in its label's words: Allopurinol, “Allopurinol is a structural analogue of the natural purine base, hypoxanthine.”; Amoxicillin, “Amoxicillin is an antibacterial drug [see Microbiology ( 12.4 )].”
Half-life, in each label's words: Allopurinol, “Elimination The half-life of allopurinol and oxipurinol are approximately 1 hour to 2 hours and 15 hours following oral …”; Amoxicillin, “Metabolism and Excretion The half-life of amoxicillin is 61.3 minutes.”
Generics: allopurinol since 1985; amoxicillin since 1974 (Drugs@FDA).
| Allopurinol | Amoxicillin | |
|---|---|---|
| Labeled for | Gout | Bacterial infections, Acid reflux and ulcers |
| Pharmacologic class | Xanthine Oxidase Inhibitor | Penicillin-class Antibacterial |
| How it works (label) | Allopurinol is a structural analogue of the natural purine base, hypoxanthine. Allopurinol acts on purine catabolism, without disrupting the biosynthesis of purines. | Amoxicillin is an antibacterial drug [see Microbiology ( 12.4 )]. |
| Half-life (label) | Elimination The half-life of allopurinol and oxipurinol are approximately 1 hour to 2 hours and 15 hours following oral dose of allopurinol, respectively. | Metabolism and Excretion The half-life of amoxicillin is 61.3 minutes. |
| Earliest approval on file (Drugs@FDA) | August 19, 1966 | January 18, 1974 |
| First generic approved | December 10, 1985 | December 9, 1974 |
| Generic labelers (NDC) | 44 labelers | 38 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0315 per tablet (Allopurinol 100 mg tablet) | $0.0788 per capsule (Amoxicillin 500 mg capsule) |
| 12-month price change | -20% | -12% |
| Boxed warning | No | No |
| Shortage now | A presentation being discontinued | No current entry |
| Recalls recorded | 6 | 12 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 155,998 | 75,926 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Allopurinol label, drug interactionsDRUG INTERACTIONS The following drugs may increase the risk of serious skin reactions: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
Allopurinol label, warnings and precautionsConcomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ].
Amoxicillin label, drug interactionsCoadministration with allopurinol increases the risk of rash.
Amoxicillin label, drug interactionsDRUG INTERACTIONS Co-administration with probenicid is not recommended. ( 7.1 ) Concomitant use of amoxicillin and oral anticoagulants may increase the prolongation of prothrombin time. ( 7.2 ) Co-administration with allopurinol increases the risk of rash. ( 7.3 ) Amoxicillin may reduce the efficacy of oral contraceptives.
Source: FDA drug labels via openFDA
What next?
- Alternatives to allopurinol
- every medicine labeled for the same conditions