Contraception Flashcards
What are the broad categories of contraception?
- Medical
- Social
- Societal
- Religious
What are the types of oral contraceptive pills?
- COCP (oestrogen and progestin)
- POP (progestin only
What are the different formulations of the COCP?
- Monophasic
- Biphasic
- Triphasic
What is the monophasic formulation of the COCP?
Each tablet contains a fixed amount of oestrogen and progestin
What is the biphasic formulation of the COCP?
Each tablet contains a fixed amount of oestogen, whilst the amount of progestin increases in the second half of the cycle
What is the triphasic formulation of the COCP?
The amonnt of oestrogen may be fixed or variable, whilst the amount of progestin increases in 3 equal phases
What are the different doses of oestrogen found in the COCP?
50, 35, 30, or 20mg/day
What does of oestrogen does NICE recommend in the COCP?
The lowest dose possible
Give two examples of forms of oestrogen found in the COCP
- Ethinylestradiol
- Mestranol
What is the half life of ethinylestradiol?
15 hours
What is the half life of mestranol?
8-24 hours
What are the routes of administration of COCP?
- Oral
- Transdermal patch
- Implants
- Nasal
- Vaginal
What kind of oestrogens can be administered orally?
Synthetic derivatives; ethinylestradiol, mestranol, valerate
What kind of progestins can be administered orally?
Synthetical derivavtives
What are the types of synthetic derivatives of progestins?
- Progesterone derivatives, e.g. medroxyprogesterone, dyhydrogesterone
- Testosterone derivatives, e.g. norethisterone, norgestrel, ethynodiol
What is the mechanism of action of the COCP?
- Suppression of ovulation
- Adverse effects on the cervical mucus
- Adverse effect on the endometrium
How does the COCP suppress ovulation?
Oestrogen inhibits the secretion of FSH via negative feedback on the anteiror pituitary, and progesterone inhibits the secretion of LH
What effect does the COCP have on cervical mucus?
Progesterone makes it more viscious, and therefore much less suitable for the passage of sperm
What effect does the COCP have on the endometrium?
It prevents the secretory phase and so the endometrium remains atrophic - this discourages implantation
What are the other ways that the COCP may prevent pregnancy?
May interfere with the cooridinated contractions of the cervix, uterus, and fallopian tubes that facilitates fertilisation and implantation
What effect does the COCP have on the hypothalamus and gonadotroph?
It holds it in a ‘ready to go’ state
What effect does the COCP have on the ovary?
It holds it in the ‘non-dominant follicular’ state
What effect does the COCP have on the endometrium?
It holds it an the atrophic state
What are the adverse effects of the COCP?
- Venous thromboembolism
- Myocardial infarction
- Hypertension
- Decrease glucose tolerance
- Increased risk of stroke in women with focal migraines
- Headaches
- Mood swings
- Cholestatic jaundice
- Increased incidence of gallstones
- Precipitate porphyria
What is the COCP metabolised by?
Hepatic cytochrome P450
What is the result of the COCP being metabolised by cytochrome P450?
Its efficacy can therefore be reduced by enzyme inducing drugs
Give three examples of types of drugs that may reduce the efficacy of the COCP?
- Anti-epileptics
- Some antibiotics
- Some natural products
Give two anti-epileptics that reduce the efficacy of the COCP?
- Carbamazepine
- Phenytoin
Give two antibiotics that affect the efficacy of the COCP
- Rifampicin
- Rifabutin
Give an example of a natural product that reduces the efficacy of the COCP
St. Johns Wort
What affect do soya proteins have on oestrogen?
It enhances its absorption, and reduces its storage and adipose on muscle, therefore reducing the half life from 15 to 7 hours
Why are soya proteins beneficial in post-menopausal women?
Because it can replace natural oestrogen
Give 4 examples of POPs
- Levonorgestral
- Norethisterone
- Ethynodiol diacetate
- Desogestrel
Give an example of a drug used in the progesterone depot
Medroxy Progesterone Acetate (MPA)
How often is MPA given in the progesterone depot?
Every 12 weeks
How can the progestin etonogestrel be administered?
- Female implants
- Male implants
- Vaginal ring
Give an example of a drug that can be used as emergency contraception up to 72 hours post coitus
Levonorgestrel
Give two examples of drugs that can be used as an emergency contraception up to 120 hours after coitus
- Ullipristal acetate
- Cu2+ IUD
What is ullipristal acetate?
A selective progesterone receptor modulator
How does the Cu2+ IUD work?
It prevents blastocyst attachment to the endometrium
