Glucocorticoids Flashcards
If cortisol secretion in the dog is 1 mg/kg/day and prednisolone is 5X as potent as cortisol, what is the dose for replacement therapy?
1/ 5= 0.2 mg/kg/day of prednisiolone (1 mg/kg/day of cortisol secretion divided by 5)
If cortisol secretion in the dog is 1 mg/kg/day and prednisolone is 5X as potent as cortisol, what is the dose for anti-inflammatory therapy?
Begin therapy at 5 x the normal cortisol secretion, then taper to the lowest dosage that control the symptoms
5 x 1/mg/kg/day= 5 mg/kg/day of cortisol
A dog would need 1 mg/kg/day of pred
If cortisol secretion in the dog is 1 mg/kg/day and prednisolone is 5X as potent as cortisol, what is the dose for immune suppression?
Begin therapy at 16 x normal cortisol secretion, then taper to the lowest dosage that controls the symptoms
16 x 1 mg/kg/day = 16 mg/kg/day or cortisol
Since pred is 5x as potent, you would need 3 mg/kg/day of pred
How do the glucocorticoid requirements of an Addisonian patient increase during stressful situations?
Supplemental glucocorticoids are needed in stress. You’ll give 3x the dose if boarding/groomer/company
What criteria are used to make dosage adjustments in Addison’s for the mineralocorticoid?
Dosage adjustments are made based on serum Na and K concentrations
What criteria are used to make dosage adjustments in Addison’s for the glucocorticoid?
Dosage adjustments are made based on clinical signs
Inappetence, vomiting, diarrhea, depression –> increase dose
Peripheral edema, PU/PD, other signs of hyperadrenocorticism dose –> decrease dose
Name the two drugs and their routes of administration used in Addison’s disease to supplement mineralocorticoids.
DOCP (desoxycorticosterone pivalate) is given once a month SQ
Fludrocortisone is given orally
What glucocorticoid is similar in potency and duration to prednisolone, but lacks its mineralocorticoid activity?
Methylprednisolone
Name a steroid known to induce surfactant production in the bovine fetus.
Dexmethasone will stimulate the type 2 alveolar cells to produce surfactant in the fetus as it crosses the placenta better than prednisolone
Classify injectable steroids as repository versus suitable for iv use. (Based on name of formulation. e.g., a succinate versus acetate.)
IV nonrepository: Succinate and phosphate
IM repository: Acetate, acetonide, and privalate
What effect does the ester formulation have on use of an oral steroid?
There is a possible link between oral use and liver cancer
Compare and contrast the benefit of steroid therapy in acute spinal cord trauma versus acute brain trauma.
Spinal cord trauma
- –injuries can be minimized by prompt treatment with high dose methylprednisolone
- –There is no benefit if given after 8 hours
- –Give 30 mg/kg IV immediately
- –Methylprednisolone has been shown to improve neurologic status and survival to discharge when administered during CPR
Brain trauma
—Injuries cannot be minimized by prompt treatment with high dose methylprednisolone
Which steroid(s) has shown the greatest utility (most evidence) in minimizing spinal cord trauma injury? Include the formulation of the steroid(s).
Methylprednisolone sodium succinate Formulation: Water soluble Can be given IV Duration is controlled by biological half-life (12-36 hours)
What are the types of cerebral edema and which are steroid responsive? Indicate the most common cause of each type of brain swelling
Interstitial cerebral edema
- —Occurs in hydrocephalus
- —Steroids help by decreasing CSF production
Vasogenic cerebral edema
- —Occurs in some brain tumors and infections
- —Responds to steroids
Cytotoxic cerebral edema
- —Occurs following trauma
- —Not steroid responsive
Explain why steroids have been hypothesized to predispose to laminitis in horses and which steroids have been most commonly implicated.
Evidence is weak
If an animal has had any predisposing factors to laminitis, steroids may increase the risk
Steroids/glucocorticoids sensitize the alpha receptors and the lamina in the hoof is a type of skin that has alpha receptors
Alpha receptors make the blood vessels constrict
The most commonly implicated are triamcinolone, dexamethasone, (and related flumetasone, and betamethasone)
Name two steroids with the lowest risk of inducing parturition in the cow in late pregnancy.
Prednisolone (probably not used), isoflupredone
Meloxizam
Which steroid is most commonly used to induce partition/abortion in cows?
Dexamethasone, betamethasone, flumethasone
At one time dexamethasone was a commonly used inhaled steroid. Why has it been largely replaced by fluticasone?
Dexamethasone had some systemic absorption and the side-effects were undesirable. The newer inhaled steroids (fluticasone) are not absorbed into the central circulation and therefore have few if any systemic side-effects
Not including reproductive effects or Cushing’s syndrome, name the six contraindications one should consider before administering a glucocorticoid.
Gastrointestinal ulceration Systemic mycoses Delayed wound healing Pancreatitis Diabetes mellitus Mycobacterial infections
Classify the common steroids as to whether they are appropriate for alternate‐day use.
Any nonrepository steroid can be used early on, but only sort or intermediate acting steroids are appropriate for alternate day use Appropriate: Hydrocortisone Prednisolone Methylprednisolone Triamcinolone
Inappropriate:
Dexmethasone
Betamethasone
Flumethasone
What advantages does alternate‐day steroid use provide over daily use?
Less immunosuppression
Less pituitary-adrenal axis suppression
If dogs are given once daily steroids, all other considerations being equal, what time of day should the dose be given and why? What about the cat?
Dogs have a diurnal rhythm, so they have a surge of cortisol in the mornings
Cats do not have a diurnal rhythm because they are possibly nocturnal
What effect do glucocorticoids have on excretion of calcium?
Glucocorticoids enhance the renal elimination of calcium
This is used to our advantage when we are treating hypercalcemia
In which species is prednisone a poor choice for a glucocorticoid and why?
Cats and horses: They do not absorb/convert prednisone well- use prednisolone
Cattle: Use prednisolone to reduce the risk of abortion or inducing parturition
How do cats differ from dogs relative to the risk of causing iatrogenic Cushing’s?
Repeated injections cause cushing’s in dogs, but not cats
How do cats differ from dogs relative to the usual dose required to achieve an equivalent effect?
Cats require 2 times the dose as a dog for the same anti-inflammatory effect
How do cats differ from dogs relative to the risk of induced diabete mellitus?
Cats treated with Depo-Medrol repeatedly are at high risk for developing diabetes
- Identify the glucocorticoids discussed that also have significant mineralocorticoid effects
Hydrocortisone
Prednisolone
- What branch of immunity is most severely impaired by steroid use? What group of infectious agents does this immunosuppression have the greatest clinical impact on?
Cell-mediated immunity
Systemic mycoses. Also true for mycobacterial infections
