etonorgestgrel

etonorgestgrel (implant)

(e to-nor-jess-trel) ,

Implanon

(trade name)

Classification

Therapeutic: contraceptive hormones
Pharmacologic: progestins

Indications

Prevention of pregnancy.

Action

Suppresses ovulation, increases viscosity of cervical mucosa and alters endometrium.

Therapeutic effects

Prevention of pregnancy.

Pharmacokinetics

Absorption: Reliably, constantly and slowly absorbed (100% bioavailable).
Distribution: Crosses the placenta and enters breast milk.
Metabolism and Excretion: Mostly metabolized by the liver.
Half-life: 25 hr.

Time/action profile

ROUTEONSETPEAKDURATION
Subdermal1 mounknown3 yr

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Known or suspected pregnancy; Active liver disease; Current/past history of thromboembolism; Active liver disease or hepatic tumors; Chronic use of drugs that induce liver enzymes; Undiagnosed abnormal genital bleeding; Known/suspected breast cancer.
Use Cautiously in: Obstetric: Lactation (may be used after 4th postpartum week); Obesity (contraceptive may be less effective); Conditions associated with fluid retention; Hypertension; Cigarette smoking or age >35 (↑ risk of thromboembolic events); Pediatric: Safe use in children <18 yr is not established; should not be used before menarche.

Adverse Reactions/Side Effects

Central nervous system

  • depression
  • dizziness
  • emotional lability
  • headache
  • nervousness

Cardiovascular

  • thromboembolic events (life-threatening)
  • hypertension

Gastrointestinal

  • hepatic adenomas

Genitourinary

  • dysmenorrhea
  • irregular/unpredictable menses
  • ↑ risk of ectopic pregnancy
  • ovarian cysts

Dermatologic

  • acne

Endocrinologic

  • breast pain
  • leukorrhea

Local

  • implant site reactions

Metabolic

  • weight gain

Musculoskeletal

  • back pain

Interactions

Drug-Drug interaction

Barbiturates, grisofulvin, rifampin, phenytoin, carbamazepine, oxcarbazepine, topiramate, modafinil induce liver enzymes and may ↓ contraceptive effectiveness.Protease inhibitors may alter blood levels and effects.Inhibitors of liver enzymes including itraconazole and ketoconazole may ↑ blood levels.St. John's wort induces liver enzymes and may ↓ contraceptive effectiveness.

Route/Dosage

Subdermal: (Adults) 1 68-mg implant, contraceptive effect lasts for 3 yr.

Availability

Subdermally implantable rod: 68 mg

Nursing implications

Nursing assessment

  • Assess BP before and periodically during therapy.
  • Assess for lower abdominal pain periodically during therapy. Patients who become pregnant with Implanon are more likely to have ectopic pregnancies.
  • Lab Test Considerations: Monitor hepatic function periodically during therapy.
    • May cause ↑ serum glucose, sodium, triglyceride, VHDL, total cholesterol, prothrombin, and factors VII, VIII, IX, and X levels. May cause ↓ LDL and antithrombin III levels. Monitor patients with diabetes, impaired glucose tolerance, and hyperlipidemias closely.
    • May initially cause ↓ thyroxine levels, followed by gradual return to baseline.
    • May ↓ sex hormone-binding globulin concentrations for first 6 mo, followed by a gradual recovery.

Potential Nursing Diagnoses

Noncompliance (Indications,  Patient/Family Teaching)

Implementation

  • Rule out pregnancy prior to inserting Implanon. If inserted according to following schedule, back-up contraception is not necessary. If deviating from recommended timing, rule out pregnancy and use a back-up non-hormonal contraceptive for 7 days after insertion.
    • If no preceding hormonal contraception, insert between Day 1 and 5 (Day 1 being first day of menstruation).
    • If switching from a combination hormonal contraceptive, insert anytime within 7 days after last active oral contraceptive tablet, anytime during 7 day ring-free period of NuvaRing, or anytime during 7 day patch-free period of transdermal contraceptive system.
    • If switching from a progestin-only method, insert any day of the month when switching from a progestin-only pill (do not skip any days between last pill and insertion), on the same day as contraceptive implant removal, on the same day as removal of a progestin-containing IUD, or on the day when the next contraceptive injection would have been.
    • Following a first-semester abortion or miscarriage, insert immediately following a complete first trimester abortion. If not inserted within 5 days insert between Day 1 and 5 of menstrual period.
    • Following delivery or a second-trimester abortion, insert between 21 and 28 days postpartum if not exclusively breast feeding or between 21 and 28 days following second-trimester abortion. If >4 weeks have elapsed, pregnancy should be excluded and patient should use a non-hormonal form of birth control during the first 7 days after insertion.
    • Always verify the presence of Implanon in the patient's arm immediately after insertion by palpitation.
  • Subdermal: Implanon implant is inserted subdermally in midportion of upper non-dominant arm about 6–8 cm above the elbow crease. Health care professionals attempting insertion or removal should be instructed in the procedures before attempting them. Must be inserted by the expiration day stated on the packaging and removed no later than 3 yrs after the date of insertion.

Patient/Family Teaching

  • Instruct patient on information on insertion and removal and provide a copy of the Patient Labeling. Patient should fill out and retain the User Card so that she will have a record of the location and when it should be removed. Advise patient to re-start contraception immediately after removal of Implanon, if she still needs to prevent pregnancy.
  • Instruct patient to notify health care profession of all Rx, OTC, and herbal products she is taking or intends to take. Advise patient that a second method of birth control should also be used during each cycle in which any of the following are used: Oral contraceptives—ampicillin, antiretroviral protease inhibitors, ketoconazole, itraconazole, barbiturates, carbamazepine, felbamate, modafinil, oxcarbazepine, penicillin V, phenylbutazone, phenytoin, rifampin, sulfonamides, tetracyclines, topiramate, valproic acid, and St. John's wort.
  • If nausea becomes a problem, advise patient that eating solid food often provides relief.
  • Inform patient that Implanon may cause unpredictable changes in vaginal bleeding patterns (changes in bleeding frequency and duration or amenorrhea). Advise patient to notify health care professional if these changes become extreme or persist.
  • May cause dizziness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
  • Advise patient to report signs and symptoms of fluid retention (swelling of ankles and feet, weight gain), thromboembolic disorders (pain, swelling, tenderness in extremities, headache, chest pain, blurred vision), mental depression, hepatic dysfunction (yellowed skin or eyes, pruritus, dark urine, light-colored stools), or abnormal vaginal bleeding. Women with a strong family history of breast cancer, fibrocystic breast disease, abnormal mamograms or cervical dysplasia should be monitored for breast cancer at least yearly. Implanon should be removed from patients who develop jaundice significant depression.
  • Instruct patient to notify health care professional if pregnancy is suspected.
  • Caution patient that cigarette smoking during estrogen therapy may increase risk of serious side effects, especially for women over age 35.
  • Advise contact lens wearers who develop visual changes or changes in lens tolerance to be examined by an ophthalmologist.
  • Caution patients to use sunscreen and protective clothing to prevent increased pigmentation.
  • Caution patient that oral contraceptives do not protect against HIV or other sexually transmitted diseases.
  • Advise patient to notify health care professional of medication regimen before treatment or surgery.
  • Emphasize the importance of routine follow-up physical exams including BP; breast, abdomen, and pelvic examinations; and Papanicolaou smears every 6–12 mo.

Evaluation/Desired Outcomes

  • Prevention of pregnancy for 3 yrs.
Mentioned in ?