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ORAL CONTRACEPTIVE PILLS (OCPs) - KDT Simplified Notes

CLASSIFICATION OF OCPs

A. ORAL PREPARATIONS

1. Combined Pill (Monophasic)

• Taken daily for 21 days, starting 5th day of menstruation; 7-day gap for withdrawal bleed
• Third generation pills (desogestrel) - better tolerated, fewer androgenic side effects

2. Phased Pill (Triphasic)

• Estrogen kept constant (30-40 mcg), progestin increases progressively in 3 phases
• Mimics natural hormonal pattern
• Examples: TRIQUILAR (6+5+10 tabs), ORTHONOVUM 7/7/7

3. Progestin-only Pill (Minipill)

• Taken daily continuously WITHOUT any gap
• Ovulation still occurs in 20-30% women
• Acts mainly via hostile cervical mucus + endometrial changes
• Efficacy: 96-98% (less than combined pill's 98-99.9%)
• Suspect pregnancy if amenorrhoea > 2 months
• Not popular; used when estrogen is contraindicated

4. Emergency (Postcoital) Pill

• Levonorgestrel = first choice; nausea/vomiting ~6% only
• Ulipristal = failure rate 1-3% (vs levonorgestrel 2-4%); extended window
• To be used ONLY for unexpected/accidental exposure (rape, condom rupture)

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B. INJECTABLE CONTRACEPTIVES

• Given during first 5 days of menstrual cycle
• Major drawback: Complete disruption of menstrual cycle / total amenorrhoea (more with DMPA)
• NOT suitable for adolescent girls or lactating mothers

C. IMPLANTS

• Subdermal; release steroid slowly over 1-5 years
• NORPLANT - 6 capsules of levonorgestrel 36 mg each (total 216 mg) - works 5 years
• Biodegradable or non-biodegradable types

D. TRANSDERMAL PATCH

• Norelgestromin + ethinylestradiol; weekly for 3 weeks, 1-week gap

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MECHANISM OF ACTION (MOA)

Table Summary - Effects of Different Hormonal Contraceptives

MOA Details:

1. Inhibition of Gn release (via FSH & LH suppression) → follicles fail to develop → Suppression of ovulation - PRIMARY mechanism of combined pill
2. Hostile cervical mucus (progestin action) - prevents sperm penetration; works with ALL methods except postcoital pill
3. Endometrial changes - hyperproliferative/hypersecretory or atrophic → blastocyst fails to implant
4. Uterine & tubal contractions modified - disfavours fertilization
5. Postcoital pill may dislodge implanted blastocyst / interfere with fertilization

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PRACTICAL CONSIDERATIONS

1. Missed pill: If 1 pill missed - take 2 next day; if >2 missed - stop course, use alternative contraception, restart on 5th day of next bleeding
2. Return of fertility: After OC - 1-2 months; After injectables - delayed by several months (may not normalize)
3. Pregnancy during OC use - terminate by suction-aspiration (risk of malformations, carcinoma in female offspring, undescended testes in male offspring)
4. Obese women need 50 mcg pill; cardiovascular risk/age >40 - use 20 mcg pill

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ADVERSE EFFECTS

A. Non-serious Side Effects (common in first 1-3 cycles, then disappear)

1. Nausea & vomiting (like morning sickness)
2. Headache (mild); migraine may worsen
3. Breakthrough bleeding/spotting (switch to triphasic or higher estrogen dose)
4. Breast discomfort

B. Side Effects Appearing Later

1. Weight gain, acne, increased body hair (androgenic - older 19-nortestosterone progestins; newer ones like desogestrel - relatively free)
2. Chloasma - pigmentation of cheeks, nose, forehead
3. Pruritus vulvae (infrequent)
4. Carbohydrate intolerance/diabetes precipitation (high-dose only; current pills - unlikely)

C. Serious Complications

1. Leg vein thrombosis & pulmonary embolism - venous thromboembolism (2-3 per 1000 women years); risk in women >35 yrs, diabetics, hypertensives, smokers - due to estrogen component
2. Coronary & cerebral thrombosis - 2 to 6-fold increase (older data); low-dose pills have smaller increase; mechanisms: increased clotting factors, decreased antithrombin III, decreased plasminogen activator, increased platelet aggregation
3. Rise in BP - 5-10% women; both estrogen and progestin responsible (via angiotensinogen & renin-aldosterone pathway); normalizes in 3-6 months after stopping
4. HDL/LDL: Estrogen raises HDL (beneficial); progestin partially nullifies this
5. Genital carcinoma - NOT increased in general population; slight breast cancer risk in current users (rare in young, considered inconsequential); PROTECTIVE against endometrial carcinoma
6. Benign hepatomas - rare; slightly higher incidence
7. Gallstones - slightly higher in OC users

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CONTRAINDICATIONS

Absolute Contraindications

1. Thromboembolic/coronary/cerebrovascular disease or history
2. Moderate-to-severe hypertension; hyperlipidaemia
3. Active liver disease, hepatoma, or jaundice during past pregnancy
4. Suspected/overt malignancy of genitals/breast
5. Porphyria
6. Impending major surgery (risk of postoperative thromboembolism)

Relative Contraindications (use under supervision)

1. Diabetes
2. Obesity
3. Smoking
4. Undiagnosed vaginal bleeding
5. Uterine leiomyoma (may enlarge with estrogen - use progestin-only)
6. Mentally ill
7. Age above 35 years
8. Mild hypertension
9. Migraine
10. Gallbladder disease

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INTERACTIONS

Enzyme Inducers (reduce OCP efficacy)

• Phenytoin, carbamazepine, primidone, rifampicin, phenobarbitone, ritonavir
• Metabolism of estrogen (estrogenic component) increased
• Switch to preparation containing 50 mcg EE or use alternative contraception
• Rifampicin is such a potent enzyme inducer - always advise alternative contraception

Suppression of Intestinal Microflora

• Ampicillin, tetracyclines - interrupt enterohepatic circulation of estrogens → blood levels fall

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OTHER HEALTH BENEFITS OF OCPs

• Lower menstrual blood loss (helps anaemia)
• Cycles become regular if irregular
• Dysmenorrhoea, premenstrual tension ameliorated
• Lower risk of endometrial and ovarian carcinoma
• Lower risk of developing colorectal cancer
• Protection from unwanted pregnancy

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Memory tip for MOA: "CHUE" - Cervical mucus hostile, Hormonal suppression (LH/FSH), Uterine/tubal changes, Endometrial changes (out of phase)