Florinef is fludrocortisone 0.1 mg, a steroid that replaces aldosterone — the hormone that controls salt and water balance. It is used mainly in adrenal insufficiency (Addison’s disease), and for low blood pressure on standing. It is a replacement hormone, and stopping it suddenly can be life-threatening.
What is Florinef?
The South African Medicine Price Registry lists Florinef Acetate as a Schedule 4 tablet containing fludrocortisone 0.1 mg.
Note the strength: a tenth of a milligram. Fludrocortisone is dosed in very small amounts, and the tablets are correspondingly small.
Fludrocortisone is a synthetic mineralocorticoid. The adrenal glands normally make two families of steroid hormone:
Glucocorticoids (cortisol) — regulating metabolism, immune function and the stress response. Replaced by hydrocortisone or prednisone.
Mineralocorticoids (aldosterone) — regulating sodium, potassium and water. Aldosterone tells the kidneys to retain sodium and water and excrete potassium, which is how blood volume and blood pressure are maintained.
Fludrocortisone replaces the second. It has strong mineralocorticoid activity and some glucocorticoid activity, which is why people with Addison’s disease usually take both fludrocortisone and hydrocortisone — they replace different hormones and neither substitutes for the other.
This is hormone replacement, not treatment. Someone taking Florinef for adrenal insufficiency is replacing something their body cannot make. That framing matters for everything below.
What is Florinef commonly used for?
- Adrenal insufficiency (Addison’s disease) — the main use, alongside hydrocortisone, replacing aldosterone the adrenal glands no longer produce.
- Congenital adrenal hyperplasia, in salt-losing forms.
- Orthostatic hypotension — blood pressure dropping on standing, causing dizziness or fainting. Fludrocortisone expands blood volume by retaining salt and water.
- Neurogenic orthostatic hypotension, in Parkinson’s disease, diabetes with autonomic neuropathy, and other nerve conditions.
- Postural orthostatic tachycardia syndrome (POTS), in some prescribing.
- Salt-wasting conditions and severe recurrent fainting, under specialist care.
The most important thing about this medicine is what happens if you stop it or get ill.
In adrenal insufficiency, the body cannot mount its own stress response. During illness, injury, surgery or vomiting, cortisol requirements rise sharply — and if replacement is not increased, the result is an adrenal crisis: collapse, very low blood pressure, and death if untreated.
Anyone on steroid replacement should:
- Know their sick day rules — usually doubling the hydrocortisone dose during fever or illness. Fludrocortisone is generally continued unchanged.
- Carry a steroid emergency card, and ideally wear medical identification.
- Have an emergency hydrocortisone injection at home, and know — along with a family member — how to use it.
- Never stop taking it, and never run out.
- Tell any doctor, dentist, paramedic or surgeon that they take steroid replacement.
Never stop Florinef abruptly. In adrenal insufficiency it is not optional.
How Florinef fits into this medicine category
| Group | Examples | What it replaces or does |
|---|---|---|
| Mineralocorticoids | Fludrocortisone (Florinef) | Aldosterone — salt, water and blood pressure |
| Glucocorticoids | Hydrocortisone, prednisone | Cortisol — metabolism, immunity, stress response |
| Compression and salt | Compression stockings, increased salt intake | Non-drug measures for orthostatic hypotension |
| Midodrine | Midodrine | Alternative for orthostatic hypotension |
| Everyday remedies | K-Fenak OTC, HP553 | Unrelated — general symptom relief |
See the general medicines hub.
What to check before using Florinef
Tell your doctor or pharmacist if you:
- Have heart failure, high blood pressure or kidney disease — fludrocortisone retains salt and water, which can worsen all three.
- Have diabetes — it can raise blood sugar.
- Have osteoporosis, glaucoma, stomach ulcers, epilepsy or thyroid disease.
- Have an active infection, including TB — a genuine consideration in South Africa.
- Take diuretics, digoxin, anti-inflammatories, warfarin, insulin or diabetes tablets, anti-epileptics or rifampicin.
- Take liquorice in quantity, which acts on the same pathway.
- Are pregnant or breastfeeding — replacement is continued, but doses may need adjusting.
- Have not had chickenpox or measles, and are exposed to someone who has.
Practical points:
- Take it at the same time each day, usually in the morning, with food.
- Keep your blood tests — potassium, sodium and kidney function are monitored, and blood pressure is checked lying and standing.
- Do not restrict salt unless told to. In adrenal insufficiency and orthostatic hypotension, adequate salt is usually part of the treatment — the opposite of general blood pressure advice.
- Never miss doses or run out. Order repeats well in advance, and keep a spare supply when travelling.
Possible cautions and when to ask a pharmacist or doctor
Effects relate mostly to salt and water retention: swollen ankles, raised blood pressure, weight gain, headache and low potassium, which causes muscle weakness and cramps.
Higher doses can produce the effects of any steroid — raised blood sugar, thinning skin, easier bruising, mood changes and greater susceptibility to infection.
Get emergency help for signs of adrenal crisis — this is the emergency to recognise:
- Severe weakness, dizziness or collapse
- Vomiting and abdominal pain
- Confusion or drowsiness
- Very low blood pressure
Say clearly that the person has adrenal insufficiency and takes steroid replacement, and give the emergency hydrocortisone injection if one is available. Treatment is straightforward when recognised and fatal when it is not.
Also get emergency help for chest pain, severe breathlessness, signs of serious infection with fever, or swelling of the face and difficulty breathing.
Contact your doctor if you develop swollen ankles or rapid weight gain, muscle weakness or cramps (possible low potassium), rising blood pressure or blood sugar, persistent dizziness on standing, or any illness with fever, vomiting or diarrhoea — that is precisely when replacement needs adjusting, and it should not wait.
Related medicine guides
Frequently asked questions
What is Florinef used for? Replacing aldosterone in adrenal insufficiency (Addison’s disease) and congenital adrenal hyperplasia, and treating low blood pressure on standing. It contains fludrocortisone 0.1 mg.
Is it the same as prednisone or hydrocortisone? No. Those replace cortisol; fludrocortisone replaces aldosterone, which controls salt and water. In Addison’s disease both are usually needed.
Why is the dose so small? Fludrocortisone is potent and is dosed in tenths of a milligram.
Can I stop taking it? No — not in adrenal insufficiency. It replaces a hormone your body cannot make, and stopping can cause a life-threatening adrenal crisis.
Should I cut down on salt? Usually the opposite. Adequate salt is generally part of the treatment for both adrenal insufficiency and orthostatic hypotension. Follow your doctor’s advice rather than general blood pressure guidance.
What are sick day rules? Increasing your steroid replacement during illness, fever, injury or surgery, because your body cannot raise its own cortisol. Make sure you know yours and that someone close to you does too.
Do I need to carry anything? Yes — a steroid emergency card, ideally medical identification, and an emergency hydrocortisone injection you and a family member know how to use.
Why the blood tests? To check potassium, sodium, kidney function and blood pressure, which fludrocortisone directly affects.