Contraceptive Patch

The combined contraceptive patch is a thin, flexible, adhesive square that releases an oestrogen and a progestin through the skin into the circulation. One patch is worn for 7 days. Three consecutive patches are used, followed by a patch-free week in which withdrawal bleeding occurs. It prevents pregnancy mainly by suppressing ovulation and gives no protection against HIV or other sexually transmitted infections.

Composition. Norelgestromin 6 mg with ethinylestradiol 0.6 mg in a 20 square centimetre patch, releasing about 150 micrograms of norelgestromin and 35 micrograms of ethinylestradiol daily. A levonorgestrel 1.5 mg with ethinylestradiol 0.75 mg patch, releasing 120 and 30 micrograms daily, exists in some markets and is restricted to patients with body mass index under 30.

Pharmacokinetics. Transdermal absorption avoids first-pass metabolism and gives steady serum levels through the week. Systemic ethinylestradiol exposure over time is higher than with a pill containing 35 micrograms, while peak levels are lower.

Effectiveness. First-year pregnancies: 8 in 100 women with typical use and 0.3 in 100 with perfect use. Pregnancy rates may be slightly higher in women weighing 90 kg or more. Risk is greatest when a patch is changed late.

Onset of protection. Immediate when the first patch is applied within 5 days of the start of menses; otherwise 7 days of backup.

Return to fertility. Without delay after stopping.

Non-contraceptive effects. Similar to the combined pill: lighter menses, less dysmenorrhoea, and lower ovarian and endometrial cancer risk. Long-term data are limited.

Suitable candidates. Patients who prefer weekly dosing to a daily tablet, who vomit or have diarrhoea or malabsorption that undermine pill absorption, and who weigh under 90 kg.

Less suitable. Weight of 90 kg or more, where efficacy may fall and another method is preferred. Skin disease at application sites such as eczema or psoriasis, adhesive allergy, or inability to keep the patch on.

Eligibility. Categories are those of every combined method.

• Category 4:
  • breastfeeding under 6 weeks; blood pressure 160/100 or more; ischaemic heart disease, stroke or complicated valvular disease; migraine with aura; current or past breast cancer.
  • current or past deep vein thrombosis or pulmonary embolism, or thrombogenic mutation; diabetes with vascular disease or more than 20 years duration; smoker 35 years or more with 15 or more cigarettes daily.
  • lupus with positive or unknown antiphospholipid antibodies; decompensated cirrhosis; liver adenoma or malignancy; major surgery with prolonged immobilisation.
• Category 3:
  • breastfeeding 6 weeks to under 6 months; not breastfeeding under 21 days postpartum; blood pressure 140/90 to 159/99; smoker 35 years or more under 15 cigarettes daily.
  • symptomatic gall bladder disease on treatment; rifampicin; rifabutin; enzyme-inducing antiseizure medicines.
• Category 2: body mass index 30 or more, age 40 years or more, sickle cell disease, uncomplicated diabetes, migraine without aura.

Investigations. Blood pressure and body mass index. Weigh the patient. No routine laboratory tests.

Interactions. Enzyme inducers lower hormone levels: rifampicin, rifabutin, phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine, griseofulvin and St John’s wort. Efavirenz, nevirapine and ritonavir-boosted regimens are category 2 and need added condoms. Lamotrigine levels fall.

Counselling points for the clinician. Venous thrombosis risk may be higher than with levonorgestrel pills in some observational data; explain the warning signs. The patch stays on during work, exercise, swimming and bathing. Consent, no coercion, assent from under 18 years.

Regimen line. Norelgestromin 6 mg with ethinylestradiol 0.6 mg patch, transdermal. Apply one patch on the same day each week for 3 weeks, then leave the fourth week patch-free. Apply to clean, dry skin on the upper outer arm, back, abdomen or buttock, never on the breasts, press for 10 seconds and run a finger around the edge. Use a different site each week. Never go more than 7 days without a patch after the patch-free week.

Each patch protects for 7 days; the patch change may be up to 48 hours late without backup. Start within 5 days of the start of menses with no backup; later starts need 7 days of backup. Weight of 90 kg or more: another method is preferred. Enzyme inducers: do not use. Postpartum: not before 21 days if not breastfeeding; breastfeeding from 6 months.

Late and detached patch rules.

Switching. From another hormonal method used correctly, start at once. From an injectable, start when the next dose is due. From an intrauterine device, start within 5 days of menses and remove the device then; if later, remove it at the next menses.

Disposal. A used patch still holds hormone: fold it with the adhesive sides together and dispose of it safely.

Follow up. Review at about 3 months and then yearly: blood pressure, weight, smoking, medicines, skin sites, bleeding. Reassess from 40 years; at about 50 years a change to a progestin-only or non-hormonal method is usual practice.

Expected effects. Skin irritation or rash at the site, bleeding changes (lighter, irregular, prolonged or absent), headache, nausea or vomiting, breast tenderness, abdominal pain, flu-like symptoms and vaginitis.

Management. Skin reaction: rotate sites, keep skin dry, and change method if severe. Frequent detachment: change method. Unscheduled bleeding: exclude pregnancy, infection, missed changes and interactions; give ibuprofen 800 mg orally three times daily for 5 days with food (maximum 2.4 g daily; avoid in renal impairment, active peptic ulcer or significant liver disease; not used in pregnancy); if bleeding persists after 3 months, change formulation or method.

Serious complications. Venous thromboembolism, stroke, myocardial infarction and hypertension.

Red flags. Severe abdominal pain, chest pain or breathlessness, severe or new headache, eye problems and severe calf pain. Remove the patch, stop the method and arrange urgent evaluation.

When to change method. Weight of 90 kg or more with pregnancy or repeated failure, category 4 condition, migraine with aura, enzyme-inducing medicines, recurrent detachment or intolerable skin reaction.

Referral and escalation. Suspected thrombosis, stroke or myocardial infarction needs emergency transfer. Persistent unexplained bleeding or an undiagnosed breast lump needs evaluation.