Hydrocortisone Drug Interactions: What to Avoid and What to Tell Your Doctor

Hydrocortisone is a powerful medication that can interact with many other drugs, supplements, and vaccines. Some interactions are mild and require monitoring; others can be serious and require immediate action. Knowing what to watch for — and what to tell your doctor — is an important part of safe hydrocortisone use.

Always give your doctor and pharmacist a complete list of your medications, including over-the-counter drugs, vitamins, and herbal supplements.

Major Interactions: Use With Caution or Avoid

Warfarin (Coumadin) — Altered Blood Clotting

Hydrocortisone can both increase and decrease the anticoagulant effect of warfarin — and the direction of the effect is unpredictable. This unpredictability makes the warfarin + hydrocortisone combination potentially dangerous. Patients on warfarin who start or stop hydrocortisone should have their INR (international normalized ratio) checked frequently until levels stabilize.

NSAIDs (Ibuprofen, Naproxen, Aspirin) — Increased GI Bleeding Risk

Combining hydrocortisone with nonsteroidal anti-inflammatory drugs (NSAIDs) significantly increases the risk of gastrointestinal ulcers and bleeding. Both drugs independently irritate the stomach lining — used together, the risk is additive. If you must use both, take them with food and ask your doctor about adding a proton pump inhibitor (PPI) like omeprazole for stomach protection.

Live Vaccines — Contraindicated at High Doses

Live or live-attenuated vaccines (such as MMR, varicella, yellow fever, and nasal influenza vaccine) are contraindicated during immunosuppressive doses of corticosteroids. The immune suppression from hydrocortisone can prevent the vaccine from working and may cause serious vaccine-strain infections. At physiological replacement doses (15-25 mg/day), vaccination decisions should be made individually with your doctor.

Moderate Interactions: Monitor Closely

Rifampin, Phenytoin, Phenobarbital — Reduced Hydrocortisone Effectiveness

These drugs are strong inducers of the CYP3A4 liver enzyme. They speed up the metabolism (breakdown) of hydrocortisone in the body, meaning hydrocortisone is eliminated faster and blood levels are lower than expected. Patients on these drugs may need a higher hydrocortisone dose to maintain adequate hormone replacement. This is especially critical for patients with adrenal insufficiency — inadequate replacement can precipitate an adrenal crisis.

Azole Antifungals (Ketoconazole, Itraconazole) — Increased Hydrocortisone Levels

Azole antifungals inhibit CYP3A4, slowing hydrocortisone metabolism. This increases hydrocortisone blood levels, amplifying both therapeutic effects and side effects. Patients taking azole antifungals may experience increased steroid side effects (blood sugar spikes, weight gain, hypertension) without an actual change in their hydrocortisone dose. Dose adjustment may be needed.

Cyclosporine and Tacrolimus — Mutual Interaction

Hydrocortisone and these immunosuppressants can interact bidirectionally — each can inhibit the metabolism of the other, potentially raising levels of both drugs. Cyclosporine may also increase the risk of seizures when combined with high-dose corticosteroids. Close monitoring of drug levels and side effects is essential in transplant patients who take both.

Potassium-Wasting Diuretics (Furosemide, Hydrochlorothiazide) — Hypokalemia Risk

Hydrocortisone causes potassium excretion through its mineralocorticoid effect. Combining it with potassium-wasting diuretics significantly increases the risk of hypokalemia (dangerously low potassium). Symptoms include muscle weakness, cramps, and irregular heartbeat. Monitor potassium levels regularly if you take both medications.

Diabetes Medications (Insulin, Metformin, GLP-1 Agonists) — Blood Sugar Disruption

Hydrocortisone raises blood glucose by stimulating liver glucose production and causing insulin resistance. If you're diabetic, starting or increasing hydrocortisone can cause your blood sugar to spike significantly. Your diabetes medication dosages may need adjustment. Monitor blood glucose closely during any changes to hydrocortisone dosing, and alert your diabetes care team.

Herbal Supplement Interactions

St. John's Wort — Reduced Hydrocortisone Effectiveness

St. John's Wort (Hypericum perforatum) is a popular herbal supplement for depression and anxiety — but it is also a potent CYP3A4 inducer, meaning it speeds up the breakdown of hydrocortisone in the body. Taking St. John's Wort can reduce hydrocortisone blood levels by a clinically significant amount, potentially leading to inadequate hormone replacement. Avoid this combination and tell your doctor if you take any herbal supplements.

Licorice Root — May Potentiate Effects

Licorice root contains glycyrrhizin, which inhibits the enzyme that converts cortisol to its inactive form. This can amplify hydrocortisone's mineralocorticoid effects, increasing blood pressure, causing sodium retention, and lowering potassium. Avoid licorice root supplements while on hydrocortisone.

What to Tell Your Doctor

Before starting or changing your hydrocortisone dose, always tell your doctor and pharmacist about:

All prescription medications (including antibiotics, antifungals, anticonvulsants, blood thinners, immunosuppressants)

All over-the-counter medications (NSAIDs like ibuprofen and naproxen, aspirin)

All vitamins and supplements (especially St. John's Wort, licorice root)

Any upcoming vaccinations — especially live vaccines

Any planned surgical procedures (which typically require stress dosing adjustments)

For information about hydrocortisone side effects and monitoring, see our companion guide: Hydrocortisone Side Effects: What to Expect and When to Call Your Doctor.