Endocrine Pharm Flashcards
what are the 3 main purposes of endocrine pharmacology
- Replace a deficiency (diabetes mellitus)
- Prevent hormone excess - or effects of (hyperadrenocorticism)
- Diagnosis (ACTH stimulation test)
what is the treatment of choice for hypothyroidism
Synthetic T4
what are the common endogenous steroid hormones
- estrogen
- progesterone
- cortizol
- aldostrone
what are the common peptide hormones
oxytocin
insulin
ATCH
what is a big difference between testing for steroid hormones vs peptide hormones?
steroid hormones are very stable, whereas peptide ones are not, and require special handling
what are your 4 options for treating hypothyroidism
- synthetic levothyroxine (T4)
- dessicated thyroid (not recommended)
- dessicated thyroglobulin (not recommended)
- synthetic liothyronine (T3) (only used in rare exceptions)
why is it important to talk to the pharmacist when prescribing synthetic T4
the bioavailability is very low in dogs compared to people
- 0.075 - 0.125 mg/kg in people
- 0.2 mg/10 kg per day in dogs
why is using dessicated thyroid difficult to use, and not recommended?
it comes from cattle or pig thyroid, makes it not very predictable and very hard to control a patient on.
what is liothyronine
synthetic T3
what is levothyroxine
synthetic T4
what is the problems with using liothyronine as a treatment modality for hypothyroid ism
liothyronine (T3) is the active form of T4 which is generally converted within tissues as it is needed.
When you give the active version you are not allowing the tissues to use it as needed and often will over medicate
is rT3 active?
NO
this is produced when you are sick, so that it is not active and slows down metabolism
is the compounded form of methimazole have good bioavailability?
yes, this is one of a few drugs that compounded medications will work.
however, the long term stability is not very good, so you should only look at prescribing a month at a time
what are some adverse drug reactions with using methimazole, and how might you avoid some of them?
GI - split dose (BID to TID) - transdermal Dermatologic - severe facial pruritis - presents in the 1st few weeks if it will happen Hepatic - reversible - monitor liver enzymes Hematologic - anemia (generally reversible) - monitor CBC
what are some problems with using transdermal methimazole?
longer absorption time
- can lead to inadequate ammounts being absorbed from many things (other cats, rubbing owners or objects, ect)
- if you need immediate results might not be the treatment modality to start with (consider pills to start then transition to transdermal)
T or F
methimazole is known for significant drug interactions
FALSE
what important considerations should be considered when you have a patient being treated with methimazole, that is now going to be treated with I-131?
methimazole can interfere with the I-131 treatment so you would need to discontinue treatment ~5-7 days prior.
would be a good idea to call where ever they will receive this treatment and get their recommendations.
T or F
restricted iodine diet is not effective in cats with naturally occurring hyperthyroidism
FALSE
restricted iodine diet is effective in 80-90% of cats with naturally occurring hyperthyroidism
the only problem is that they have to be on a VERY strict diet
- no treats unless correct ones
- no hunting (iodine found in rodents as well)
- can’t sneak other cats food
what are the options for treating hyperthyroidism
- T4 treatment
- Iodine restriction
- i.e. diet
- I-131
- surgery
- consider consequences of removing parathyroid as well
however, if you are not managing it well you can cause kidney issues. Typically a mild hyperthyroid state is better for keeping kidney Dz at bay
if this happens you can supplement with synthetic T4 to help.
