Combined Transdermal Patch (CPT)

Question 1

What are the 3 types of combined hormonal contraceptives (CHCs)?

Answer 1

Combined hormonal contraceptives (CHCs):

1. Oral contraceptives
2. Transdermal patch
3. Vaginal ring

Question 2

Briefly describe the mechanism of action of CPT

Answer 2

• CPT act primarily to inhibit ovulation.
  
  • Ovulation is inhibited by the oestrogen and progestogen components which act on the hypothalamo-pituitary axis to reduce production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). With no surge in LH and FSH to stimulate the ovaries, ovulation does not occur.
• CPT also have contraceptive effects on cervical mucus and the endometrium.
  
  • The oestrogen component causes the endometrium to proliferate and grow.
  • The progestogen component prevents hyperplasia of the endometrium by opposing the proliferative effects of oestrogen.

Question 3

What are the indications of CPT?

Answer 3

• Contraception
• Hyperandrogenism (e.g. acne, hirsutism)
• Menstrual cycle disorders (e.g. menorrhagia, dysmenorrhea)
• Symptom control in endometriosis and leiomyomas

Question 4

What is the most common regime to take CPT?

Answer 4

Apply a patch on the same day each week for 3 consecutive weeks (days 1, 8, and 15), have a patch-free interval on week 4 (days 22–28), then start a new cycle.

Question 5

What are the health benefits of CPT?

Answer 5

• Reduced risk of ovarian, endometrial and colorectal cancer;
• Predictable bleeding patterns
• Reduced dysmenorrhoea and menorrhagia;
• Management of symptoms of polycystic ovary syndrome (PCOS), endometriosis and premenstrual syndrome;
• Improvement of acne;
• Reduced menopausal symptoms;
• Maintaining bone mineral density in peri-menopausal females under the age of 50 years.

Question 6

What are the side effects of CPT?

Answer 6

• Nausea and abdominal pain
• Headache
• Breast pain and/or tenderness
• Mood swings
• Minor skin irritation at the site of application

Question 7

What are the risks of CPT?

Answer 7

• Cardiovascular disease and stroke
  
  • Hypertension and myocardial infarction
• Venous thromboembolism
• Breast cancer
• Cervical cancer

Question 8

What are the contra-indications of CPT?

Answer 8

• BMI greater than 35
• Breast feeding
• Smoking over the age of 35
• Hypertension
• History of or family history of venous thromboembolisms
• Prolonged immobility due to surgery or disability
• Diabetes mellitus with complications e.g. retinopathy
• History of migraines with aura
• Breast cancer or primary liver tumours

Question 9

What is the guidance of vomiting or diarrhoea on CPT?

Answer 9

• Vomiting and diarrhoea do not affect the bioavailability of the CPT
• No additional contraception (such as condoms) are needed if a woman vomits or has diarrhoea whilst using the CPT

Question 10

Briefly describe how to assess a woman for CPT

Answer 10

• Check the UK Medical Eligibility Criteria
• Enquire specifically about:
  
  • Migraine
  • Cardiovascular risk factors such as smoking, obesity, hypertension, previous venous thromboembolism, hyperlipidaemia and thrombophilia
  • Past and current medical conditions
  • Family history

Question 11

What is the efficacy of CPT?

Answer 11

• When the CPT is used perfectly→ 0.3% of women will conceive within the first year of use due to method failure
• When the CPT is used typically→ 9% will conceive within the first year of use due to method failure or user failure

Question 12

What are the advantages of CPT?

Answer 12

• The patch is applied once weekly, so is more convenient than taking a pill every day
• Patches do not become less effective if the user vomits or has diarrhoea→ hormones are absorbed through the skin, not through the gastrointestinal tract
• The patch is as effective as combined oral contraceptives (COCs) at preventing pregnancy

Question 13

What are the disadvantages of CPT?

Answer 13

• It can be seen
• It may become detached (partially or fully) from the skin, compromising efficacy
• It is less effective in women who weigh more than 90 kg
• Risks and adverse effects, such as skin irritation, nausea and vomiting, and unscheduled bleeding may occur
• There may be a delay in return to normal fertility after stopping the patch