fludrocortisone vs phenytoin

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Side-by-side comparison of fludrocortisone 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

Barbiturates, phenytoin, or rifampin – increased metabolic clearance of fludrocortisone acetate because of the induction of hepatic enzymes.

Drug Class
fludrocortisone Mineralocorticoid
phenytoin Anticonvulsant (Hydantoin)
Type
fludrocortisone Prescription
phenytoin Prescription
Summary
fludrocortisone

Fludrocortisone is a medicine that helps your body balance salt and fluids. It is used when your adrenal glands don't make enough of certain hormones.

phenytoin

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

What It Treats
fludrocortisone

This medicine is used to treat Addison's disease and salt-losing adrenogenital syndrome. These conditions happen when your adrenal glands don't make enough of certain hormones. Fludrocortisone helps your body hold onto salt and water, which is important for these conditions.

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
fludrocortisone

Fludrocortisone is a mineralocorticoid. It works by helping your body to retain sodium and water. This helps to increase blood volume and blood pressure.

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
fludrocortisone
  • High blood pressure
  • Swelling in your hands, feet, or ankles
  • Enlarged heart
  • Heart failure
  • Loss of potassium
phenytoin

No common side effects listed.

FAERS Reports
fludrocortisone
  • Feeling tired 146
  • Falling down 144
  • Feeling lightheaded 135
  • Feeling sick to your stomach 129
  • Death 126
phenytoin
  • Drug Interaction 1,547
  • Seizure 1,382
  • Toxicity To Various Agents 1,353
  • Convulsion 1,262
  • Status Epilepticus 791
Serious Warnings
fludrocortisone

This medicine may cause you to retain too much sodium and water, leading to high blood pressure, swelling, and heart problems. Tell your doctor right away if you have any of these symptoms. This medicine can also interact with other medicines, so be sure to tell your doctor about all the medicines you are taking.

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
fludrocortisone

Talk to your doctor if you are pregnant or breastfeeding before taking this medicine. It is not known if this medicine will harm your unborn baby. It is also not known if this medicine passes into breast milk.

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.

How to Read This fludrocortisone vs phenytoin Comparison

fludrocortisone is classified in the Mineralocorticoid 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, fludrocortisone has 680 submissions while phenytoin has 6,335. 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 speeds up how fast your liver processes fludrocortisone. this can cause the fludrocortisone to leave your system too quickly to work well.. 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 fludrocortisone or phenytoin.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.