Hormonal Contraception: Comprehensive Clinical Pharmacotherapy and Management

Contraceptive Use and Pharmacist Role in the United States

• Demographics (2022-2023): Approximately $54.3\%$ of females aged $15$ through $49$ were utilizing some form of contraception during this period.
• Common Methods: The most frequently reported methods in the United States include:
      * Female sterilization.
      * The birth control pill.
      * Male condoms.
      * Long-Acting Reversible Contraceptives (LARC).
• Historical Context:
      * The FDA approved the first birth control pill in May $1960$.
      * John Rock, MD, was the lead gynecologist in the initial clinical studies.
      * The initial oral contraceptive (OC) marketed in $1960$ was significantly more potent than modern versions, containing $150\,\mu g$ of ethinyl estradiol and $90\%$ more progestin.
• Pharmacist Prescribing Rights:
      * Regulations vary significantly by state.
      * States determine specific requirements for pharmacist training, the minimum age of the patient served, and the specific types of contraceptives included in the prescribing scope.

Common Abbreviations and Definitions

• CHC: Combined Hormonal Contraceptive.
• COC: Combined Oral Contraceptive.
• OCP: Oral Contraceptive Pill.
• BC: Birth Control.
• POP: Progesterone-Only Pill (commonly referred to as the "mini-pill").
• IUD: Intrauterine Device.
• LARC: Long-Acting Reversible Contraceptive.
• EC: Emergency Contraceptive.

Comparative Efficacy of Contraceptive Methods

Method effectiveness is categorized by unintended pregnancy rates within the first year of use.

• Least Effective Methods (Approx. $70\%$ to $82\%$ effective):
      * Chance (No Method): Typical use: $85\%$; Perfect use: $85\%$.
      * Spermicides: Typical use: $28\%$.
      * Periodic Abstinence: Typical use: $24\%$; Perfect use range: $0.4\%$ to $5\%$.
      * Withdrawal: Typical use: $22\%$; Perfect use: $4\%$.
      * Sponge (Parous): Typical use: $24\%$.
      * Sponge (Nulliparous): Typical use: $12\%$.
      * Female Condom: Typical use: $21\%$.
      * Male Condom: Typical use: $18\%$; Perfect use: $2\%$.
• Moderately Effective Methods ($6\%$ to $12\%$ failure rates):
      * Injectable MPA (Depo-Provera): Typical use: $6\%$; Perfect use: $0.2\%$.
      * COC, POP, Transdermal Patch, and Vaginal Ring: Typical use: $9\%$; Perfect use: $0.3\%$.
      * Diaphragm: Typical use: $12\%$.
• Most Effective Methods (LARC and Sterilization - Greater than $99\%$ effective):
      * Copper IUD (ParaGard): Typical use: $0.8\%$; Perfect use: $0.6\%$.
      * Levonorgestrel IUD (Mirena/Skyla): Typical use: $0.2\%$; Perfect use: $0.2\%$.
      * Implant (Implanon/Nexplanon): Typical use: $0.05\%$; Perfect use: $0.05\%$.
      * Male Sterilization (Vasectomy): Typical use: $0.15\%$.
      * Female Sterilization: Typical use: $0.5\%$.

Mechanisms of Action for Hormonal Contraceptives

• Estrogens:
      * Inhibit ovulation by suppressing Follicle Stimulating Hormone (FSH), which prevents the development of a dominant follicle.
      * Inhibition of implantation.
      * Acceleration of ovum transport.
      * Induction of luteolysis.
• Progestins:
      * Inhibit ovulation by suppressing Luteinizing Hormone (LH) secretion (the LH surge).
      * Production of thick cervical mucus to reduce sperm penetration into the ovum.
      * Slowing of ovum transport.
      * Inhibition of implantation by altering the endometrial lining.

Combined Oral Contraceptive (COC) Preparations and Dosing

• Estrogen Dosage Tiers:
      * High Dose: $50\,\mu g$ ethinyl estradiol.
      * Low Dose: $30$ to $35\,\mu g$ ethinyl estradiol.
      * Very Low Dose: $10$ to $25\,\mu g$ ethinyl estradiol.
• Cycle Length Options:
      * 21-day active / 7-day placebo.
      * 24-day active / 4-day placebo.
      * 84-day active / 7-day placebo (Extended Cycle).
      * Continuous active pills (No placebo interval).
• Dosing Adjustments within Cycles:
      * Monophasic: Same dose of estrogen and progestin throughout the active pill phase.
      * Multiphasic (Biphasic, Triphasic, Quadriphasic): Varying doses to mimic the natural menstrual cycle.
• Unique Characteristics: Some formulations include a low dose of estrogen or iron during the final placebo/reminder week instead of inert tablets.

Non-Contraceptive Benefits and Health Effects

• Clinical Benefits:
      * Treatment of Premenstrual Dysphoric Disorder (PMDD) and cyclical mood complaints.
      * Reduction in dysmenorrhea and anemia.
      * Management of menstrual-related migraines (specifically those without aura).
      * Improvement in acne and benign breast disease (higher progestin/lower estrogen is preferred for the latter).
      * Decreased frequency of bacterial vaginosis.
• Cancer Risk Reductions (Significantly reduced in OC users):
      * Ovarian Cancer: Reductions increase with longer duration of use. (Havrilesky OR: $0.73$, $95\%\text{ CI: } 0.66$-$0.81$; Iversen IRR: $0.67$, $99\%\text{ CI: } 0.5$-$0.89$).
      * Endometrial Cancer: (Havrilesky OR: $0.57$, $95\%\text{ CI: } 0.43$-$0.76$; Iversen IRR: $0.66$, $99\%\text{ CI: } 0.48$-$0.89$).
      * Colorectal Cancer: (Havrilesky OR: $0.86$, $95\%\text{ CI: } 0.79$-$0.95$; Iversen IRR: $0.81$, $99\%\text{ CI: } 0.66$-$0.99$).
• Cancer Risks (Minimal Increases):
      * Breast Cancer: Slight increase in users (OR: $1.08$). Relative Risk (RR) for current/recent users is $1.2$. Risk increases to RR $1.38$ after $10\text{ or more years}$ of use. This equates to $1$ extra case for every $7690$ women using hormonal contraception for one year. No increased risk in mortality was found (OR: $0.94$).
      * Cervical Cancer: Mentioned as a potential risk factor with hormonal use.

Identifying and Managing Side Effects

Hormone Excess Symptoms

• Estrogen Excess: Nausea, bloating, cervical mucorrhea/polyposis, melasma, migraine headaches, hypertension, edema, cyclic weight gain, breast tenderness, and VTE risk.
• Progesterone Excess: Fatigue, hypomenorrhea, depression, hair loss, and vaginal candidiasis.
• Androgenic Activity (Related to Progestin): Increased appetite, weight gain, hirsutism, and acne.

Hormone Deficiency Symptoms

• Estrogen Deficiency: Early or midcycle breakthrough bleeding (BTB) (Days $1$ through $14$), increased spotting, hypomenorrhea, irritability, depression, hot flashes, atrophic vaginitis, and dyspareunia.
• Progesterone Deficiency: Late BTB (Days $14$ through $21$) and hypermenorrhea.

Specific Management Strategies

• Nausea: Common in the first $2$ to $3\text{ months}$; take with food or at bedtime.
• Headaches: If headaches occur during the placebo week (likely due to estrogen withdrawal), shorten the hormone-free interval (e.g., $24/4$ or $84/4$ cycles) or provide a small dose of estrogen during that week.
• Breakthrough Bleeding (BTB):
      * Common in the first $2$ to $3\text{ months}$; wait at least $3\text{ months}$ before switching products.
      * Lower estrogen doses carry a higher risk of BTB.
      * For extended-cycle users, if BTB occurs after $21\text{ days}$ of active pills, the patient can discontinue pills for $3$ to $4\text{ days}$ (once per month maximum) to allow for a withdrawal bleed, then restart.

U.S. Medical Eligibility Criteria (US MEC) Categories

• Category 1: No restriction for the use of the contraceptive method.
• Category 2: Advantages generally outweigh theoretical or proven risks.
• Category 3: Theoretical or proven risks usually outweigh advantages.
• Category 4: Represents an unacceptable health risk.

Clinical Precautions and Contraindications

• Category 4 (Absolute Contraindications for CHC):
      * Migraines with aura.
      * Smoking ($15\text{ or more cigarettes/day}$) and age $\geq 35$.
      * Surgery with prolonged immobilization.
      * Chronic Kidney Disease (CKD) with nephrotic syndrome or dialysis.
      * History of DVT/PE with high risk of recurrence.
      * Postpartum ( < 21\text{ days} regardless of breastfeeding status).
• Venous Thromboembolism (VTE) Risk:
      * Estrogens increase coagulability by increasing clotting factors ($VII$, $X$, and fibrinogen) and platelet counts.
      * $3rd\text{ generation progestins}$ (desogestrel) and $4th\text{ generation progestins}$ (drospirenone) may carry higher risks.
      * Yasmin Data: Users: $7.2\text{ to } 12.5 \text{ cases per } 10,000\text{ woman-years}$; Non-users: $1\text{ to } 5\text{ per } 10,000\text{ woman-years}$.
      * The VTE risk with CHC is half as high as the risk during pregnancy.
• Postpartum Timing for CHC starting:
      * Breastfeeding: Category $3$ between $21\text{ to } 30\text{ days}$; Category $2$ if > 42\text{ days}.
      * Non-breastfeeding: Category $2$ between $21\text{ to } 42\text{ days}$ (without other risk factors); Category $1$ if > 42\text{ days}.

Drug and Supplement Interactions

• Anticonvulsants (Phenytoin, Carbamazepine, Barbiturates, Primidone, Topiramate, Oxcarbazepine): Categorized as Category 3. These induce enzymes that decrease contraceptive efficacy. If a COC is used, a minimum of $30\,\mu g$ EE is required.
• Lamotrigine: CHCs can decrease Lamotrigine levels, potentially increasing seizure risk in monotherapy patients (Category 3).
• Rifampin/Rifabutin: Strong enzyme induction; reduces efficacy significantly (Category 3). Backup contraception is required for short courses; alternative methods are recommended for long courses.
• Antivirals: Fosamprenavir may decrease levels of CHC, and the CHC may decrease levels of fosamprenavir (Category 3).
• Sugammadex (General Anesthesia Antidote): Binds with progesterone; backup contraception is required for $7\text{ days}$ after administration.
• St. John's Wort: May decrease efficacy (Category 2).
• Vitamin C: Increases estrogen absorption by $50\%$. Doses should be separated.

The "ACHES" Warning System for Severe Risks

Patients should seek immediate medical attention if they experience:

• A - Abdominal Pain: May indicate gallbladder disease, hepatic adenoma, blood clots, or pancreatitis.
• C - Chest Pain (SOB/Coughing blood): May indicate Myocardial Infarction (MI) or Pulmonary Embolism (PE).
• H - Headaches (Severe): May indicate stroke, hypertension, or migraine headache.
• E - Eye Problems (Blurred/Flashing/Blindness): May indicate stroke, hypertension, or vascular problems.
• S - Severe Leg Pain: May indicate Deep Vein Thrombosis (DVT).