Reason for switching
The National Patient Safety Alert (NPSA) on steroid emergency cards highlights that missing doses of corticosteroids when on long-term and/or high dose therapy can risk adrenal insufficiency or even adrenal crisis, which is a medical emergency.
In some cases, prescribers may need to switch from oral prednisolone to intravenous (IV) hydrocortisone. For example when people:
- have severe vomiting, persistent diarrhoea or other severe illness
- have gastrointestinal obstructions that reduce the absorption of medicines given orally
- are not allowed to have any form of food, drink or medicine by mouth
These situations may be temporary and require IV hydrocortisone to replace the oral prednisolone and avoid the risk of adrenal crisis.
Always confirm why the switch from oral prednisolone to IV hydrocortisone is required and refer to the steroid sick day rules. A switch to IV hydrocortisone may not always be needed.
Considerations for switching
Consider the following points before switching between formulations.
The available UK formulations are:
- oral prednisolone – tablet, soluble tablet, gastro-resistant tablet, and oral solution
- IV hydrocortisone – solution for injection, powder for solution for injection, and powder with solvent for solution for injection
Hydrocortisone has a 1 to 1 ratio for glucocorticoid (anti-inflammatory) and mineralocorticoid (water retention) properties.
Prednisolone has a 4 to 0.8 ratio for glucocorticoid (anti-inflammatory) and mineralocorticoid (water retention) properties.
The relatively high mineralocorticoid activity of hydrocortisone makes it unsuitable for disease suppression on a long-term basis.
Switch individuals from IV hydrocortisone to an oral corticosteroid as soon as possible. This may mean restarting their oral prednisolone at a higher dose than they were previously on and weaning back to baseline.
When comparing anti-inflammatory potency, 5mg of oral prednisolone is equipotent to 20mg of oral hydrocortisone.
Oral hydrocortisone has a bioavailability of near 100%.
Based on this, 5mg of oral prednisolone is similar in anti-inflammatory potency to 20mg of IV hydrocortisone.
Local policies for IV hydrocortisone administration may differ. Please refer to your local policy in the first instance.
For IV hydrocortisone
The following points should be considered when switching to IV hydrocortisone:
- doses usually range from 100mg to 500mg
- injection doses can be repeated at intervals of 2, 4 or 6 hours
- injections are usually administered over 1 to 10 minutes
- infusions are usually administered over 20 to 30 minutes or as a continuous infusion
- the plasma half-life is about 100 minutes. This is nearly double for prednisolone.
For planned operations
There is no specific guidance on how to switch from oral prednisolone to IV hydrocortisone. Based on the glucocorticoid potency and bioavailability, it should be possible to switch from one formulation to the other without a delay in dosing.
The risk of adrenal insufficiency and adrenal crisis outweighs the risk of additive side effects from prednisolone and hydrocortisone exposure.
The dose of oral prednisolone will depend on the indication.
The usual dose varies between 5mg and 60mg once a day but higher doses may be prescribed.
Confirm the route and indication of hydrocortisone with the prescriber.
Refer to the guidelines for the management of glucocorticoids during the peri-operative period for patients with adrenal insufficiency for dosing advice before, during and after surgery. IV hydrocortisone doses are likely to be higher during times of surgical stress.
Note, 5mg oral prednisolone is similar in anti-inflammatory potency to 20mg IV hydrocortisone.
Refer to your local IV hydrocortisone administration policy to identify which salt to use and the strengths available.
There are 3 hydrocortisone injections available:
- hydrocortisone sodium phosphate
- hydrocortisone sodium succinate
- hydrocortisone acetate
In some cases, you may need to use part of an IV hydrocortisone vial.
The total daily dose of IV hydrocortisone should be divided for repeated administration.
IV hydrocortisone injection doses can be repeated at intervals of 2, 4 or 6 hours.
A 30-year-old lady has been on long-term 5mg oral prednisolone once a day for rheumatoid arthritis. She now has a bowel obstruction and requires switching of her oral corticosteroid to IV hydrocortisone. The following steps will help you determine an appropriate dose for this patient.
- 5mg oral prednisolone is similar in anti-inflammatory potency to 20mg IV hydrocortisone
- the dose of IV hydrocortisone will be 5mg given 4 times a day or 20mg given as a continuous IV infusion over 24 hours
- the IV hydrocortisone dose can be administered regardless of the timing of the last oral prednisolone dose
Monitoring after the switch
The is no guidance on what should be monitored after switching from oral prednisolone to IV hydrocortisone.