Weight Gain with Fludrocortisone 0.1 mg
The available evidence does not directly address weight gain specifically from fludrocortisone 0.1 mg, as this is a mineralocorticoid used primarily for sodium retention rather than a glucocorticoid; however, based on the mechanism of action involving sodium and water retention, patients can expect modest weight gain of approximately 1-3 kg, primarily from fluid retention rather than fat mass accumulation.
Critical Distinction: Mineralocorticoid vs. Glucocorticoid Effects
Fludrocortisone is a mineralocorticoid, not a glucocorticoid, and causes weight gain through a fundamentally different mechanism than the corticosteroids discussed in most available literature 1
The weight gain from fludrocortisone is primarily fluid retention from sodium and water reabsorption, not the increased appetite and fat mass accumulation seen with glucocorticoids 2
Glucocorticoids cause weight gain through increased caloric intake and fat deposition, with studies showing 1-5 kg weight gain over 1-2 years at doses of 5-10 mg prednisolone 1
Expected Weight Gain Pattern with Fludrocortisone
In patients with Addison's disease receiving 0.3 mg daily of fludrocortisone (three times the 0.1 mg dose in question), all patients retained sodium and water and gained weight, though the specific amount was not quantified 2
At the standard 0.1 mg dose, patients were found to be sodium and water depleted, suggesting this dose causes minimal to no weight gain 2
Most patients required 0.2 mg of fludrocortisone to maintain adequate sodium and water balance, suggesting 0.1 mg produces limited fluid retention effects 2
When fludrocortisone dose was increased from undertreated levels to therapeutic levels (0.2-0.3 mg), some patients developed edema, indicating the weight gain is fluid-based 2
Clinical Monitoring Approach
For patients on fludrocortisone 0.1 mg:
Expect 1-2 kg weight gain maximum from fluid retention, occurring within the first few weeks of therapy 2
Monitor for signs of excessive mineralocorticoid effect: peripheral edema, hypertension, hypokalemia 2
Measure plasma renin activity to assess adequacy of mineralocorticoid replacement rather than relying solely on weight changes 2
Document baseline weight before initiating therapy, as recommended by the American College of Rheumatology for corticosteroid monitoring 3
Important Caveats
Concomitant glucocorticoid therapy is the primary concern:
If the patient is also taking glucocorticoids (hydrocortisone, prednisone, etc.), the glucocorticoid component will cause significantly more weight gain than the fludrocortisone 1, 3
Glucocorticoids are strongly associated with weight gain, particularly in the first 9 months of treatment, with mean gains of 2.7 kg in patients treated ≤1 year 1
The American College of Rheumatology notes that concomitant glucocorticoid use is the medication most likely to cause weight gain in patients on multiple medications 3
Other weight-promoting medications (gabapentin, pregabalin, amitriptyline, paroxetine) may contribute additional weight gain 3
Practical Clinical Guidance
If weight gain exceeds 2 kg in a month or ≥7% from baseline:
Systematically review all concurrent medications for weight-promoting agents, as recommended by the Journal of the American Medical Association 3
Evaluate specifically for glucocorticoid use, as these are most likely to cause problematic weight gain 3
Assess for signs of mineralocorticoid excess: check blood pressure, serum potassium, and consider reducing fludrocortisone dose if edema develops 2
The weight gain from fludrocortisone 0.1 mg alone should be self-limiting once sodium and water balance is achieved, typically within 2-4 weeks 2