Block 5 Drugs

Question 1

Oral contraceptives: Combined oestrogen and progesterone

Answer 1

• Oestrogen/progesterone pill

Suppresses the release of FSH and LH, which are needed for ovulation: ovulation therefore suppressed, pregnancy cannot occur.

Pros:

• 99.8% effective
• Decrease risk of ovarian cysts/cancers
• Decrease risk of anaemia
• Progestogens decrease risk of endometrial cancers
• Relief of acne, endometriosis symptoms, dysmenorrhoea and menorrhagia

Cons:

• Breast tenderness
• Decreased libido
• Increased risk of CV compications: stroke, HTN, IHD, thromboembolism
• Increased risk of breast cancer with long term use
• Risk of depression

Question 2

Progesterone only oral contraceptive

MoA

Side Effects

Answer 2

Progesterone alone suppresses ovulation by acting on the anterior pituitary and hypothalamus to suppress LH and FSH synthesis. High progesterone in the follicular phase inhibits ovulation, thickens cervical mucus (reducing sperm motility) and inhibits endometrial gland development.

Pros:

• Can be used in place of combined oral contraceptive when oestrogen is contraindicated.
• Useful in emergency contraception

Cons:

• Not 100% effective, less effective than combined pill
• Side effects: acne, significant nausea, depression