Androgen Pharmacology

Question 1

Testosterone levels fluctuate, but the daily secretion range for males is __________ and females is __________.

Answer 1

5 - 7 ng; 0.25 ng

Question 2

Highest levels of testosterone are around ________.

Answer 2

8 AM (500-700 ng/dl)

Question 3

Hypogonadism is considered _________.

Answer 3

testosterone less than 200 ng/dl

Question 4

In which patients is testosterone used?

Answer 4

Hypogonadal boys
Patients with osteoporosis
Aging men (questionable)
AIDS patients with cachexia

Question 5

Gynecomastia, low libido, and low bone density are associated with ____________.

Answer 5

low estrogen

Question 6

Parenteral testosterone decreases spermatogenesis. Why?

Answer 6

It suppresses the production of LH and FSH.

Question 7

Which types of testosterone have androgenic activity?

Answer 7

All of them. All testosterones have anabolic and androgenic activity.

Question 8

The disadvantage of testosterone patches is ______________.

Answer 8

high frequency of skin rash (up to 1/3 of patients)

Question 9

Which formula of testosterone causes the most consistent plasma level of testosterone?

Answer 9

Transdermal gel

Question 10

A frequent side effect of oral testosterone is ________________.

Answer 10

hepatotoxicity (specifically cholestatic jaundice)

Question 11

True or false: testosterones can cause anemia.

Answer 11

False. They stimulate RBC production and thus treat anemia form low EPO.

Question 12

Which enzyme is inhibited by the drug that can treat ACTH-independent Cushing’s?

Answer 12

Ketoconazole inhibits 17-alpha hydroxylase

Question 13

Why do some birth controls treat acne?

Answer 13

Estrogen increases the expression of sex-hormone-binding globulin which lowers the level of free testosterone. In females, there is no sensing mechanism to increase testosterone production, so the levels stay down and sebum production decreases (because sebum production is stimulated by testosterone).

Question 14

What do the -lutamide drugs do?

Answer 14

Block androgen receptors!

Enzalutamide and bicalutamide

Question 15

Which drugs block 5-alpha reductase?

Answer 15

Finasteride (commonly given in BPH)

Question 16

What is the main benefit of using androgen receptor antagonists as opposed to the former practice of using a once daily agonist (that leads to pituitary suppression)?

Answer 16

The agonists have flare symptoms when given in large doses.

Question 17

What two hormones are needed for spermatogenesis?

Answer 17

FSH and testosterone

Question 18

Where does negative feedback from LH and FSH occur?

Answer 18

LH stimulates androgen production, which acts in negative feedback on the pituitary and hypothalamus, while FSH stimulates production of inhibin which only acts on the pituitary.

Question 19

What percent of testosterone is made by the testes and adrenal glands?

Answer 19

Testes: 95%

Adrenal glands: 5%

Question 20

When should you consider testosterone supplementation?

Answer 20

In men who have had multiple testosterone levels below 200 ng/dl and who are having symptoms of low testosterone (such as decreased libido, erectile dysfunction, gynecomastia, or small testes)

Question 21

Why is methyltestosterone not used?

Answer 21

It is hepatotoxic. It has the advantage of being less affected by first-pass metabolism, but it is too toxic to use. (Specifically, it can cause cholestatic jaundice.)

Question 22

What are some side effects of testosterone?

Answer 22

Physiologic doses have the exact same as physiologic testosterone: acne, gynecomastia, and aggression. Supraphysiologic doses cause testicular shrinkage, decreased spermatogenesis, and psychiatric disturbance.

Question 23

Which adrenal enzyme is inhibited by ketoconazole?

Answer 23

17-alpha hydroxylase

Question 24

Which suffix is found in GnRH antagonists?

Answer 24

-relix

Degarelix and ganirelix