Please read first: This article is for general information only and is not medical advice. Adrenal insufficiency is a serious, lifelong condition. Always follow the personal plan from your own doctor or endocrinologist, and consult your doctor or pharmacist for advice specific to your medications.
If you take hydrocortisone as replacement therapy for adrenal insufficiency or Addison's disease, take a missed dose as soon as you remember, then contact your doctor for a plan. This is not like most missed doses. When you are sick or under stress, a missed hydrocortisone dose can trigger adrenal crisis, a life-threatening emergency. Do not skip doses.
Why this missed dose is not like the others
For almost every other medication, the standard advice is the same: take the dose when you remember, and if it is nearly time for the next one, skip it and never double up. You have probably read that line a hundred times, including in our own guide to medications you should never skip.
Hydrocortisone for adrenal insufficiency breaks that rule.
Your adrenal glands normally make cortisol, a hormone the body cannot live without. In adrenal insufficiency and Addison's disease, the glands do not make enough, so cortisol is replaced with hydrocortisone taken by mouth, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). You are not treating a symptom. You are replacing a hormone your body needs every single day to keep your blood pressure, blood sugar, and salt balance stable.
That is why MedlinePlus is blunt about it: "Never skip doses of your medicine for this condition because life-threatening reactions may occur." A short course of a steroid like prednisone for swelling or a flare is a different situation. Replacement hydrocortisone is keeping you alive.
The rule that flips: sick days mean more, not less
Here is the part that surprises people. For most drugs, being sick does not change the missed-dose math. For replacement hydrocortisone, illness and stress are exactly when your body needs the most cortisol, and when a missed dose is most dangerous.
A healthy body pumps out extra cortisol during a fever, an infection, an injury, or surgery. Your adrenal glands cannot do that anymore, so the extra has to come from your medicine. The FDA prescribing information for hydrocortisone states that "in patients on corticosteroid therapy subjected to unusual stress, increased dosage of rapidly acting corticosteroids before, during, and after the stressful situation is indicated."
MedlinePlus lists the triggers that usually mean you need a temporary increase: infection, injury, stress, and surgery. Doctors call this "stress dosing" or "sick-day rules." The Endocrine Society's clinical guideline recommends adjusting the glucocorticoid dose to the severity of the illness.
We are not going to print numbers here, and you should be careful with any page that does. How much extra, and for how long, is a personal decision your endocrinologist sets for you in advance. If you do not have a written sick-day plan yet, that is the single most important thing to ask for at your next visit. This is also the opposite of the advice for many other drugs you may take, like the ones in our guide to medications to stop when you are sick. Hydrocortisone is the one you increase, not pause.
Why the morning dose matters most
Cortisol follows a daily rhythm. Levels are highest when you wake up and taper off through the day. Good replacement copies that pattern. The Endocrine Society guideline advises that the highest dose be given in the morning at awakening, with the rest split across the day, which is why hydrocortisone is usually taken two or three times a day.
So a missed morning dose is a bigger deal than a missed evening one. Morning is when your body expects the most cortisol, and it is when running short leaves you weak, foggy, and shaky for the rest of the day. A late evening dose, by contrast, is usually the smallest. This is different from drugs like tacrolimus, where doses are steady across the day, so the timing of a miss matters less.
| Situation | Typical missed-dose advice for most drugs | Replacement hydrocortisone (adrenal insufficiency) |
|---|---|---|
| You just realized you missed a dose | Take it, unless it is nearly time for the next one | Take it as soon as you remember, then follow your doctor's plan |
| You are sick with a fever or infection | No change to the missed-dose rule | You likely need more, not less. Follow your sick-day plan |
| Doubling up | Usually warned against | Never adjust on your own. Your endocrinologist sets the plan |
| You are vomiting and cannot keep pills down | Wait and retake later | Treat as an emergency. This can lead to adrenal crisis |
Know the warning signs of adrenal crisis
This is the part clinical pages tend to bury, and it is the part that saves lives. If a missed dose stacks on top of illness, or if you cannot keep your medicine down, your cortisol can drop dangerously low. NIDDK is direct: if not treated right away, adrenal crisis can cause death. The severe shortage can cause life-threatening low blood pressure, low blood sugar, low sodium, and high potassium.
MedlinePlus lists warning signs to watch for:
- Sudden, severe pain in the belly, lower back, or legs
- Vomiting and diarrhea, especially if you cannot keep pills down
- Dizziness or lightheadedness, and low blood pressure
- Difficulty breathing
- Confusion or a reduced level of consciousness
If you have these symptoms, this is a 911 situation. MedlinePlus advises that if you cannot give yourself your emergency injection, go to the nearest emergency room or call 911. Tell the responders you have adrenal insufficiency and need hydrocortisone. That one sentence changes how fast you are treated. The same urgency applies to other can't-miss medicines we cover. A gap has real consequences with the seizure medicine Keppra, and with clozapine, Gilenya, and Vemlidy.
Your emergency kit and medical ID
Because a missed dose during illness can escalate, most people with adrenal insufficiency are set up ahead of time. The Endocrine Society guideline recommends that every patient be equipped with a glucocorticoid injection kit for emergency use and taught how to use it, for the times when vomiting makes pills useless. Some people with Addison's disease, or their family members, are taught to give an emergency hydrocortisone injection during a crisis.
The guideline also recommends a steroid emergency card and medical alert identification, and NIDDK advises carrying your injection and wearing medical alert identification at all times. If you take hydrocortisone for adrenal insufficiency and do not have these yet, they belong on your next appointment list.
How Pillo helps you not miss in the first place
The best crisis is the one that never starts, and that comes down to two things: taking the right dose at the right time every day, and knowing whether you actually took it.
That is where a reminder built for complex schedules helps. Pillo supports a multi-dose daily routine, so your larger morning dose and your smaller later doses each get their own reminder at the right time. The persistent alarm keeps going until you confirm you took the dose, so a busy morning does not quietly turn into a skipped one. And because Pillo keeps a dose log, when you ask yourself "wait, did I take my morning dose?" you can check instead of guess, which is exactly the doubt that leads to a missed or doubled dose. If you get sick, that same log gives you and your doctor a clear record to build your sick-day response around.
Download Pillo on Google Play to set up a schedule that matches your cortisol rhythm. Pillo is available on Android.
Frequently Asked Questions
What happens if you miss a dose of hydrocortisone?
Take the missed dose as soon as you remember, then contact your doctor. Because hydrocortisone replaces a hormone your body needs to survive, MedlinePlus warns to never skip doses because life-threatening reactions may occur. A single missed dose when you are otherwise well is usually manageable, but a missed dose during illness, vomiting, or major stress can lead to adrenal crisis and needs urgent attention.
Can you double up on hydrocortisone if you miss a dose?
Do not change your own dose. Unlike sick-day dosing, which your endocrinologist plans with you in advance, doubling up on your own is not a do-it-yourself decision. Take the missed dose when you remember and follow the written plan your doctor gave you. If you are worried you took too much, you can call Poison Control at 1-800-222-1222.
Does a missed morning dose of hydrocortisone matter more than an evening one?
Yes. Replacement dosing copies your natural cortisol rhythm, and the Endocrine Society guideline advises the highest dose in the morning. Missing that morning dose leaves you short during the part of the day when your body expects the most cortisol, so it tends to hit harder than a missed evening dose.
What are the signs of an adrenal crisis?
Warning signs include severe pain in the belly, back, or legs, vomiting and diarrhea, dizziness, low blood pressure, difficulty breathing, and confusion, per MedlinePlus. Adrenal crisis is a medical emergency that can cause death if not treated right away. Call 911 and say you have adrenal insufficiency.
Do I need to call my doctor after missing a dose of hydrocortisone?
If you feel fine and it was a single missed dose while you were well, take it and mention it at your next visit. But call your doctor promptly if you are sick, if you missed more than one dose, or if you cannot keep your pills down. Reach out sooner if you feel any warning signs of adrenal crisis.
A final note: This article provides general information and is not a substitute for professional medical advice. Adrenal insufficiency care is highly individual. Always consult your doctor or pharmacist before making any changes to your medication routine, and follow the personal sick-day and emergency plan your endocrinologist sets for you.
