Implantable_Contraceptives_Flashcards

Question 1

What was the original non-biodegradable subdermal contraceptive implant?

Answer 1

Implanon, which has been replaced by Nexplanon.

Question 2

What are the two main differences between Nexplanon and Implanon?

Answer 2

The applicator has been redesigned to prevent ‘deep’ insertions, and Nexplanon is radiopaque making it easier to locate if impalpable.

Question 3

What hormone do both versions release?

Answer 3

The progestogen hormone etonogestrel.

Question 4

Where is the implant typically inserted?

Answer 4

In the proximal non-dominant arm, just overlying the tricep.

Question 5

What is the main mechanism of action of implantable contraceptives?

Answer 5

Preventing ovulation and thickening the cervical mucus.

Question 6

What is the effectiveness of implantable contraceptives?

Answer 6

Highly effective with a failure rate of 0.07/100 women-years.

Question 7

How long do implantable contraceptives last?

Answer 7

They last for 3 years.

Question 8

Why can implantable contraceptives be used in women with a past history of thromboembolism or migraine?

Answer 8

Because they do not contain oestrogen.

Question 9

When can implantable contraceptives be inserted following a termination of pregnancy?

Answer 9

Immediately following a termination of pregnancy.

Question 10

What are the disadvantages of implantable contraceptives?

Answer 10

The need for a trained professional to insert and remove the device, and additional contraceptive methods needed for the first 7 days if not inserted on day 1 to 5 of a woman’s menstrual cycle.

Question 11

What are the main adverse effects of implantable contraceptives?

Answer 11

Irregular/heavy bleeding, headache, nausea, breast pain.

Question 12

How is irregular/heavy bleeding managed with implantable contraceptives?

Answer 12

Using a co-prescription of the combined oral contraceptive pill and performing a speculum exam/STI check if bleeding continues.

Question 13

What drugs may reduce the efficacy of Nexplanon?

Answer 13

Enzyme-inducing drugs such as certain antiepileptics and rifampicin.

Question 14

What does the FSRH advise for women on enzyme-inducing drugs?

Answer 14

They should switch to a method unaffected by enzyme-inducing drugs or use additional contraception until 28 days after stopping the treatment.

Question 15

What are the UKMEC 3 contraindications for implantable contraceptives?

Answer 15

Ischaemic heart disease/stroke (for continuation, if initiation then UKMEC 2), unexplained, suspicious vaginal bleeding, past breast cancer, severe liver cirrhosis, liver cancer.

Question 16

What are the UKMEC 4 contraindications for implantable contraceptives?

Answer 16

Current breast cancer.

Question 17

summarise implantable contraceptives

Answer 17

Implantable contraceptives

Implanon was the original non-biodegradable subdermal contraceptive implant which has been replaced by Nexplanon. From a pharmacological perspective Nexplanon is the same as Implanon. The two main differences are:
the applicator has been redesigned to try and prevent ‘deep’ insertions (i.e. subcutaneous/intramuscular)
it is radiopaque and therefore easier to locate if impalpable

Both versions slowly releases the progestogen hormone etonogestrel. They are typically inserted in the proximal non-dominant arm, just overlying the tricep. The main mechanism of action is preventing ovulation. They also work by thickening the cervical mucus.

Key points
highly effective: failure rate 0.07/100 women-years - it is the most effective form of contraception
long-acting: lasts 3 years
doesn’t contain oestrogen so can be used if past history of thromboembolism, migraine etc
can be inserted immediately following a termination of pregnancy

Disadvantages include
the need for a trained professional to insert and remove device
additional contraceptive methods are needed for the first 7 days if not inserted on day 1 to 5 of a woman’s menstrual cycle

Adverse effects
irregular/heavy bleeding is the main problem: this is sometimes managed using a co-prescription of the combined oral contraceptive pill. It should be remembered to do a speculum exam/STI check if the bleeding continues
‘progestogen effects’: headache, nausea, breast pain

Interactions
enzyme-inducing drugs such as certain antiepileptic and rifampicin may reduce the efficacy of Nexplanon
the FSRH advises that women should be advised to switch to a method unaffected by enzyme-inducing drugs or to use additional contraception until 28 days after stopping the treatment

Contraindications
UKMEC 3*: ischaemic heart disease/stroke (for continuation, if initiation then UKMEC 2), unexplained, suspicious vaginal bleeding, past breast cancer, severe liver cirrhosis, liver cancer
UKMEC 4**: current breast cancer

*proven risks generally outweigh the advantages
**a condition which represents an unacceptable risk if the contraceptive method is used

Question 18

A 34-year-old female presents to a Family Planning clinic. She is interested in having a Nexplanon inserted. What is the main adverse effect she should be counselled about?

Increased risk of cervical cancer
Increased risk of venous thromboembolism
Irregular menstrual bleeding
Increased risk of stroke
Increased risk of endometrial cancer

Answer 18

Irregular menstrual bleeding

The correct answer is Irregular menstrual bleeding. The Nexplanon implant, which contains the progestin etonogestrel, mainly functions by inhibiting ovulation. However, it also alters the endometrium and cervical mucus, which can lead to changes in menstrual bleeding patterns. According to UK guidelines, up to 1 in 5 women may experience amenorrhoea after a year of use, while others may have frequent or prolonged bleeding. Therefore, it’s crucial to counsel patients about this potential side effect before insertion.

The option Increased risk of cervical cancer is incorrect. While high-risk human papillomavirus (HPV) infection is a well-established risk factor for cervical cancer, there’s no evidence linking progestin-only contraceptives like Nexplanon with an increased risk of cervical cancer.

Similarly, the option Increased risk of venous thromboembolism is not accurate. Combined hormonal contraceptives (containing both estrogen and progesterone) are known to increase the risk of venous thromboembolism due to their influence on coagulation factors. However, progestin-only methods such as Nexplanon do not carry this increased risk.

The claim of an Increased risk of stroke is also incorrect for Nexplanon users. Again, this elevated risk is associated with combined hormonal contraceptives rather than progestin-only methods due to the presence of estrogen.

Finally, the assertion that there’s an Increased risk of endometrial cancer with Nexplanon use is inaccurate as well. In fact, progestins have been shown to reduce the incidence of endometrial hyperplasia and carcinoma by opposing estrogen’s proliferative effect on the endometrium.