Sex Steroid Drugs ie oral contraceptives, HRT

Question 1

What are the 3 types of COCP?

Answer 1

1) Monophasic - all tablets have fixed amount of oestrogen + progesterone
2) Biphasic - fixed oestrogen, ^progesterone in 2nd half
3) Triphasic - fixed oestrogen, increasing levels of progesterone

Question 2

Which type of COCP is the first-line choice for most women?

Answer 2

• Monophasic with lowest concentration of oestrogen (to minimise VTE risk)

Question 3

What is the mechanism of action of the COCP?

Answer 3

• Oestrogen inhibits FSH and progesterone inhibits LH = suppresses ovulation
• Progesterone thickens cervical mucus = hostile for sperm and implantation

Question 4

Name some ADRs of the COCP:

Answer 4

• VTE, MI, stroke
• Hypertension
• Mood swings
• Gallstones + cholestatic jaundice
• Headaches
• Decreased glucose tolerance
• Porphyria

Question 5

Explain why the efficacy of the COCP is reduced if taken with other drugs such as phenytoin/carbamazepine/rifampicin/St.John’s Wort:

Answer 5

The COCP is metabolised by CYP450.

These drugs are CYP450 inducers, so will increase the clearance of the COCP.

Question 6

What is the mechanism of action of the Progestin-Only Pill?

Answer 6

Progesterone thickens cervical mucus, making it hostile to sperm and implantation

Question 7

Name some ADRs of the Progestin-Only Pill:

Answer 7

• Breast tenderness
• Mood swings
• Heavy bleeding or spotting
• Abdominal cramps

Question 8

POP or COCP?

Answer 8

• COCP more effective as prevents ovulation

- POP indicated in women with risk factors for VTE, or experience other side effects on COCP

Question 9

What are the choices for emergency contraception?

Answer 9

High dose Progestin:

• Levonorgestrel <72hrs post-coitus
• Ullipristal acetate <120hrs

Copper IUD <120hrs

Question 10

What are the indications for HRT?

Answer 10

Menopausal symptoms ie:

• Hot flushes
• Dyspareunia
• Diaphoresis

Question 11

What are the 2 main types of HRT?

Answer 11

1) Sequential = 28 days of oestrogen, 14/28 with progesterone to mimic normal cycle and can cause normal periods
2) Continuous = 28 days of oestrogen + progesterone, doesn’t cause menstrual bleeding

Question 12

Why is HRT (combined hormone replacement therapy) normally prescribed rather than ERT (oestrogen replacement therapy)?

Answer 12

Progestin inhibits the proliferative effects of oestrogen, reducing the risk of endometrial/ovarian cancer

Question 13

Name some ADRs of HRT:

Answer 13

• Breast cancer
• ^stroke risk
• Thromboembolism
• Headache
• Diarrhoea
• Abdominal cramps

Question 14

What are the indications for the use of Clomifene?

Answer 14

Female infertility due to ovulatory dysfunction

Question 15

What is the mechanism of action of Clomiphene?

Answer 15

Inhibits oestrogen binding in the anterior pituitary
= Increases FSH levels
= Induces ovulation

Question 16

What are the indications of Tamoxifen?

Answer 16

• Pre- and perimenopausal women with oestrogen-receptor-positive breast cancer
• Anovulatory infertility
• Gynaecomastia

Question 17

What is the mechanism of action of Tamoxifen?

Answer 17

• Tamoxifen binds to the oestrogen-receptors in the breast to prevent cell division
• Also binds to oestrogen-receptors in hypothalamus, causing increased gonadotrophin release to induce ovulation

Question 18

What are the indications of Mifepristone?

Answer 18

Termination of pregnancy (medically or mechanically)

Labour induction in fetal death

Question 19

What is the mechanism of action of Mifepristone?

Answer 19

• Inhibits progesterone binding