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glipizide vs phenytoin

Side-by-side comparison of glipizide and phenytoin. 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

These drugs include the thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blocking drugs, and isoniazid.

Recommendation: Your doctor may need to monitor your blood sugar more closely and adjust your medication dose if necessary.

Drug Class
glipizide Sulfonylurea
phenytoin Anticonvulsant (Hydantoin)
Type
glipizide Prescription
phenytoin Prescription
Summary
glipizide

Glipizide is a medicine that helps lower blood sugar in adults with type 2 diabetes. It works along with diet and exercise.

phenytoin

Phenytoin injection is used to treat certain types of seizures. It can also prevent seizures during or after neurosurgery.

What It Treats
glipizide

Glipizide is used to improve blood sugar control in adults who have type 2 diabetes. It is meant to be used in addition to diet and exercise. This medicine helps your body use insulin better and lowers blood sugar levels.

phenytoin

This medicine treats generalized tonic-clonic status epilepticus, a type of prolonged seizure. It also helps prevent and treat seizures that may happen during or after brain surgery. Sometimes, it can be used for a short time instead of the oral form of phenytoin when you cannot take the medicine by mouth.

How It Works
glipizide

Glipizide belongs to a class of drugs called sulfonylureas. It works by helping your pancreas release more insulin. Insulin then helps your body use sugar from the food you eat.

phenytoin

Phenytoin works by slowing down the signals in the brain that cause seizures. It stabilizes nerve cell membranes, reducing excessive electrical activity. This helps to prevent seizures from starting or spreading.

Common Side Effects
glipizide
  • Nausea
  • Diarrhea
  • Skin rash
  • Dizziness
  • Drowsiness
phenytoin

No common side effects listed.

FAERS Reports
glipizide
  • High blood sugar 6,673
  • Feeling sick to your stomach 4,442
  • Loose, watery stools 3,266
  • Feeling tired 2,999
  • Weight loss 2,811
phenytoin
  • The medicine is reacting with another medicine 1,547
  • Seizure 1,382
  • Poisoning from different substances 1,353
  • Convulsion 1,260
  • Prolonged seizure 790
Serious Warnings
glipizide

Glipizide can cause low blood sugar (hypoglycemia). Watch for symptoms like shakiness, sweating, confusion, and rapid heartbeat. If you have very low blood sugar, get medical help right away. Certain drugs can increase the risk of low blood sugar. Tell your doctor about all the medicines you take.

phenytoin

This medicine can cause serious heart problems if given too quickly. The injection rate should not be faster than 50 mg per minute for adults, and 1 to 3 mg/kg/min (or 50 mg per minute, whichever is slower) for children. Your heart will be monitored closely during and after the injection.

Pregnancy
glipizide

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if glipizide will harm your unborn baby. Talk to your doctor about the best way to control your blood sugar during pregnancy. It is not recommended to breastfeed while taking this medication.

phenytoin

Taking phenytoin during pregnancy may increase the risk of birth defects. If you are pregnant or plan to become pregnant, talk to your doctor about the risks and benefits of this medicine.

Also Compare, Nearby Drugs

How to Read This glipizide vs phenytoin Comparison

glipizide is classified in the Sulfonylurea drug class, while phenytoin sits within the Anticonvulsant (Hydantoin) 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, glipizide has 20,191 submissions while phenytoin has 6,332. 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 phenytoin can interfere with how glipizide controls blood sugar, potentially causing your blood sugar levels to rise.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between glipizide and phenytoin - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.