Steroid Conversion Calculator

A Steroid Conversion Calculator helps clinicians, pharmacists, students, and informed patients translate a dose of one corticosteroid into the equivalent dose of another. This is essential when switching medications (e.g., prednisone → dexamethasone), converting between oral and parenteral forms, or checking total steroid exposure during short-term therapy.

What the Steroid Conversion Calculator Does

The calculator converts a given dose of one glucocorticoid to an equivalent dose of a different glucocorticoid using established potency equivalence factors. It answers questions like:

• “If a patient is on 20 mg prednisone daily, what is the equivalent dexamethasone dose?”
• “How much methylprednisolone equals 5 mg prednisolone?”
• “What is the total daily prednisone-equivalent for multiple steroid sources?”

It does not replace clinical judgment about tapering, adrenal suppression, or indications — those require clinical context.

The Principle & Formula

Each corticosteroid has a relative glucocorticoid potency compared to hydrocortisone. The conversion uses these potency ratios.

Basic formula:
TargetDose = SourceDose × (SourcePotency / TargetPotency)

Where potency is expressed as mg of hydrocortisone equivalent per mg of drug (or the inverse depending on table structure). For clarity below, we use a common clinical equivalence table and convert via the prednisone-equivalent approach.

An alternative straightforward method uses a reference drug (commonly prednisone or hydrocortisone):

1. Convert source dose → prednisone-equivalent.
2. Convert prednisone-equivalent → target dose.

Common Corticosteroid Equivalence Table (Glucocorticoid potency)

Note: values shown are widely used clinical approximations.

Interpretation: 5 mg prednisone ≈ 20 mg hydrocortisone ≈ 0.75 mg dexamethasone.

How the Calculator Works (step-by-step)

1. Select source steroid (e.g., prednisone) and enter the dose (e.g., 20 mg).
2. Select target steroid (e.g., dexamethasone).
3. The calculator uses the table above to convert:

Example using the two-step method:

• Convert source to prednisone-equivalent: if source is prednisone, pred_eq = sourceDose.
• Convert prednisone-equivalent to target:
  targetDose = pred_eq × (prednisone_equiv_mg / target_equiv_mg)

Because prednisone ≈ 5 mg in the table, and dexamethasone ≈ 0.75 mg:

targetDose = sourceDose × (5 / 0.75)

But if the source is not prednisone, first convert it to hydrocortisone or prednisone equivalent then to the target.

Worked Example

Problem: Convert 40 mg prednisone to dexamethasone equivalent.

1. Prednisone ≈ 5 mg unit; dexamethasone ≈ 0.75 mg unit.
2. Using direct ratio: TargetDose = 40 mg × (5 / 0.75)? That would be wrong because 5 mg is prednisone equivalence — better to convert via hydrocortisone or use relative potency carefully.

Better, use conversion via hydrocortisone:

• Hydrocortisone equivalence: prednisone 5 mg = hydrocortisone 20 mg. So prednisone potency factor = 20/5 = 4 hydrocortisone mg per prednisone mg.
• Dexamethasone: 0.75 mg = hydrocortisone 20 mg → dex potency factor = 20/0.75 ≈ 26.667 hydrocortisone mg per dex mg.

Now convert 40 mg prednisone → hydrocortisone equivalents: 40 × 4 = 160 mg hydrocortisone equivalent.

Convert hydrocortisone equivalent to dexamethasone: targetDose = 160 / 26.667 ≈ 6 mg dexamethasone.

So 40 mg prednisone ≈ 6 mg dexamethasone (approximate). You can also do it via prednisone→pred_eq→target: pred_eq = 40 (prednisone mg), dex = pred_eq × (pred_equiv_mg / dex_equiv_mg) = 40 × (5 / 0.75) = 40 × 6.6667 = 266.67 — obviously wrong because units mismatch — so always use consistent reference (hydrocortisone or prednisone equivalence correctly).

(For practical clinical use many clinicians use quick reference conversion charts rather than manual algebra to avoid sign errors.)

Practical Uses

• Switching inpatient IV corticosteroids to equivalent oral doses on discharge.
• Calculating cumulative steroid exposure (e.g., prednisone-equivalent mg/day).
• Adjusting therapy when formulary availability forces a switch in agent.
• Pharmacy cross-checking for dosing accuracy.

Important Clinical Considerations & Caveats

1. Mineralocorticoid effects differ. Hydrocortisone has significant mineralocorticoid activity; dexamethasone has negligible. Equivalent glucocorticoid potency does not equal equivalent mineralocorticoid activity. This matters for blood pressure, sodium retention, and adrenal replacement.
2. Half-life and duration: Some steroids (dexamethasone, betamethasone) are longer-acting; a single-equivalent dose may have different clinical effects over time.
3. Route matters: Bioavailability for oral vs. IV is usually similar for many agents, but formulate-specific differences exist. Conversion assumes systemic bioavailability.
4. Adrenal suppression & tapering: Long-term systemic steroid use suppresses the HPA axis. Dose equivalence does not tell you when and how to taper — tapering requires clinical judgement; consult specialists.
5. Pediatric and renal/hepatic adjustments: Children and patients with organ dysfunction need individualized dosing.
6. Not for anabolic steroid (AAS) use: This guide covers therapeutic corticosteroids (anti-inflammatory, immunosuppressive). It does not support anabolic steroid dosing or illicit use.

Quick Reference: Convert via Prednisone-Equivalent

If you prefer prednisone-equivalent shortcuts, first convert each drug to its prednisone-equivalent (using table), sum prednisone-equivalents when multiple steroids are present, then convert that total to the desired drug.

Safety & Legal Notice

This article is informational and not medical advice. Never change or substitute steroid medication without consulting the prescribing clinician or pharmacist. Improper use of systemic corticosteroids can cause serious harm (adrenal crisis, immunosuppression, hyperglycemia, psychiatric effects).

20 Frequently Asked Questions (FAQs)

1. What is the Steroid Conversion Calculator for?
   To convert doses between systemic corticosteroids (e.g., prednisone ↔ dexamethasone).
2. Are corticosteroid conversions exact?
   They are approximate clinical equivalents; individual response can vary.
3. Can I use this for topical or inhaled steroids?
   No — topical and inhaled potency and systemic absorption differ; use product-specific guidance.
4. Is mineralocorticoid activity accounted for?
   No — conversions reflect glucocorticoid potency only.
5. How do I convert multiple steroid doses into a single equivalent?
   Convert each to prednisone- or hydrocortisone-equivalent and sum them.
6. Does route (oral vs. IV) change equivalence?
   Usually not for commonly used systemic steroids, but check bioavailability for specific drugs.
7. Is dexamethasone always better because it’s potent?
   Not necessarily — potency, duration, and side-effect profile determine best choice.
8. Can I self-taper using equivalent doses?
   Tapering should be supervised by a clinician; equivalence is only one factor.
9. Does pregnancy change conversion?
   Pregnancy alters pharmacokinetics; consult obstetric care providers.
10. Are these values valid for children?
    Equivalence holds, but pediatric dosing is weight-based and needs pediatric expertise.
11. Can I convert topical steroid strength with this tool?
    No — topical potency scales are different.
12. What about inhaled corticosteroids?
    Inhaled agents (e.g., budesonide vs. fluticasone) have separate equivalence charts.
13. Do I need to consider steroid interactions?
    Yes — drugs that induce/inhibit metabolism (CYP enzymes) can change effective exposure.
14. Can the calculator help estimate adrenal suppression risk?
    It helps estimate cumulative exposure; clinical assessment is required for suppression risk.
15. Is betamethasone stronger than dexamethasone?
    They are similar; betamethasone is slightly more potent per common tables.
16. How accurate is the conversion for very high doses?
    Still approximate — pharmacodynamics may change at supraphysiologic doses.
17. What if I’m switching formulations (e.g., IV methylpred → oral prednisone)?
    Use equivalence tables and clinician input; account for immediate clinical needs.
18. Can I use this for veterinary medicine?
    Species differences matter; consult veterinary references.
19. Where do these equivalence numbers come from?
    They are standard clinical references derived from pharmacologic studies and common practice.
20. Who should I contact for a specific patient conversion?
    Talk to the treating physician, clinical pharmacist, or endocrinologist.

Final Notes

A Steroid Conversion Calculator is a practical, time-saving clinical tool—handy for clinicians, pharmacists, and trainees. Use it to check doses and plan conversions, but always combine its output with clinical judgment, patient-specific factors, and specialist advice for safe steroid management. If you want, I can produce a ready-to-use conversion table or a simple step-by-step calculator logic you can integrate into your site or tool — tell me which format you prefer.