aprepitant


aprepitant (oral)

(a-prep-i-tant) aprepitant,

Emend

(trade name)

fosaprepitant (injection)

(fos-a-prep-i-tant) fosaprepitant,

Emend

(trade name)

Classification

Therapeutic: antiemetics
Pharmacologic: neurokinin antagonists
Pregnancy Category: B

Indications

Oral: Intravenous: Prevention of:
  • Acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic chemotherapy,
  • Nausea and vomiting associated with initial and repeat courses of moderately emetogenic chemotherapy.
Oral: Prevention of postoperative nausea and vomiting.

Action

Acts as a selective antagonist at substance P/neurokinin 1 (NK1) receptors in the brain.

Therapeutic effects

Decreased nausea and vomiting associated with chemotherapy.Augments the antiemetic effects of dexamethasone and 5-HT3 antagonists (ondansetron).

Pharmacokinetics

Absorption: 60–65% absorbed following oral administration. Following IV administration, fosaprepitant is rapidly converted to aprepitant, the active component.Distribution: Crosses the blood brain barrier; remainder of distribution unknown.Metabolism and Excretion: Mostly metabolized by the liver (CYP3A4 enzyme system); not renally excreted.Half-life: Aprepitant—9–13 hr.

Time/action profile (antiemetic effect)

ROUTEONSETPEAKDURATION
PO1 hr4 hr*24 hr
IVrapidend of infusion*24 hr
*Blood level

Contraindications/Precautions

Contraindicated in: Hypersensitivity;Concurrent use with pimozide (risk of life-threatening adverse cardiovascular reactions); Lactation: May cause unwanted effects in nursing infants.Use Cautiously in: Concurrent use with any agents metabolized by CYP3A4; Obstetric: Use only if clearly needed; Pediatric: Safety not established.

Adverse Reactions/Side Effects

Cardiovascular

  • dizziness
  • fatigue
  • weakness

Dermatologic

  • stevens-johnson syndrome (life-threatening)

Gastrointestinal

  • diarrhea

Miscellaneous

  • hiccups
  • hypersensitivity reaction (flushing, erythema, dyspnea) (IV)

Interactions

Drug-Drug interaction

Aprepitant inhibits, induces, and is metabolized by the CYP3A4 enzyme system; it also induces the CYP2C9 system. Concurrent use with other medications that are metabolized by CYP3A4 may result in ↑ toxicity from these agents including docetaxel, paclitaxel, etoposide, irinotecan, ifosfamide, imatinib, vinorelbine, vinblastine, vincristine, midazolam, triazolam, and alprazolam ; concurrent use should be undertaken with caution.Concurrent use with drugs that significantly inhibit the CYP3A4 enzyme system including (ketoconazole, itraconazole, nefazodone, clarithromycin, ritonavir, nelfinavir, and diltiazem ) may ↑ blood levels and effects of aprepitant.Concurrent use with drugs that induce the CYP3A4 enzyme system including rifampin, carbamazepine, and phenytoin may ↓ blood levels and effects of aprepitant.↑ blood levels and effects of dexamethasone (regimen reflects a 50% dose reduction); a similar effect occurs with methylprednisolone (↓ IV dose by 25%, ↓ PO dose by 50% when used concurrently).May ↓ the effects of warfarin (careful monitoring for 2 wk recommended), oral contraceptives (use alternate method), and phenytoin.

Route/Dosage

Prevention of Nausea and Vomiting Associated with Highly Emetogenic Chemotherapy

Oral (Adults) 125 mg 1 hr prior to chemotherapy (Day 1) (with dexamethasone 12 mg PO 30 min prior to chemotherapy and a 5-HT3 antagonist prior to chemotherapy), then 80 mg once daily for 2 days (Days 2 and 3) (with dexamethasone 8 mg once daily for 3 days [Days 2–4]).Intravenous (Adults) Single-dose regimen—150 mg 30 min prior to chemotherapy on Day 1 (with dexamethasone 12 mg PO 30 min prior to chemotherapy and a 5-HT3 antagonist prior to chemotherapy). Continue dexamethasone on Days 2–4 (8 mg PO on Day 2, 8 mg twice daily on Days 3 and 4); 3–day regimen—115 mg 30 min prior to chemotherapy on Day 1 (with dexamethasone 12 mg PO 30 min prior to chemotherapy and a 5-HT3 antagonist prior to chemotherapy). Continue aprepitant 80 mg PO on Days 2 and 3. Continue dexamethasone 8 mg once daily on Days 2–4.

Prevention of Nausea and Vomiting Associated with Moderately Emetogenic Chemotherapy

Oral (Adults) 125 mg 1 hr prior to chemotherapy (Day 1) (with dexamethasone 12 mg PO 30 min prior to chemotherapy and a 5-HT3 antagonist), then 80 mg once daily for 2 days (Days 2 and 3).Intravenous (Adults) 115 mg 30 min prior to chemotherapy on Day 1 (should be given with dexamethasone 12 mg PO 30 min prior to chemotherapy and a 5-HT3 antagonist). Continue aprepiptant 80 mg PO once daily on Days 2 and 3.

Prevention of Postoperative Nausea and Vomiting

Oral (Adults) 40 mg given within 3 hr prior to induction of anesthesia.

Availability

Capsules: 40 mg, 80 mg, 125 mg Lyophilized solid (requires reconsititution prior to injection): 115 mg/vial, 150 mg/vial

Nursing implications

Nursing assessment

  • Assess nausea, vomiting, appetite, bowel sounds, and abdominal pain prior to and following administration.
  • Monitor hydration, nutritional status, and intake and output. Patients with severe nausea and vomiting may require IV fluids in addition to antiemetics.
  • Assess for rash periodically during therapy. May cause Stevens-Johnson syndrome. Discontinue therapy if severe or if accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis and/or eosinophilia.
  • Lab Test Considerations: Monitor clotting status closely during the 2 wk period, especially at 7–10 days, following aprepitant therapy in patients on chronic warfarin therapy.
    • May cause mild, transient ↑ in alkaline phosphatase, AST, ALT, and BUN.
    • May cause proteinuria, erythrocyturia, leukocyturia, hyperglycemia, hyponatremia, and ↑ leukocytes.
    • May cause ↓ hemoglobin and WBC.

Potential Nursing Diagnoses

Risk for deficient fluid volume (Indications)
Imbalanced nutrition: less than body requirements (Indications)

Implementation

  • For chemotherapy, aprepitant is given as part of a regimen that includes a corticosteroid and a 5-HT3 antagonist (see Route/Dosage).
  • Oral: Administer daily for 3 days. Day 1—administer 125 mg 1 hr prior to chemotherapy. Days 2 and 3—administer 80 mg once in the morning. May be administered without regard to food.
  • Intravenous Administration
  • Single-Dose Regimen: Intermittent Infusion: Inject 5 mL of 0.9% NaCl for Injection into vial. Swirl gently; avoid shaking or jetting saline into vial. Diluent: Prepare an infusion bag of 145 mL 0.9% NaCl. Withdraw entire volume from vial, and transfer to infusion bag for a total volume of 150 mL. Concentration: 1 mg/mL. Gently invert bag 2–3 times. Solution is stable for 24 hr at room temperature. Inspect solution for particulate matter. Do not administer solutions that are discolored or contain particulate matter.
  • Rate: Infuse over 20–30 min.
  • 3-Day Regimen: Intermittent Infusion: Inject 5 mL of 0.9% NaCl for Injection into vial. Swirl gently; avoid shaking or jetting saline into vial. Diluent: Prepare an infusion bag of 110 mL 0.9% NaCl. Withdraw entire volume from vial, and transfer to infusion bag for a total volume of 115 mL. Concentration: 1 mg/mL. Gently invert bag 2–3 times. Solution is stable for 24 hr at room temperature. Inspect solution for particulate matter. Do not administer solutions that are discolored or contain particulate matter.
  • Rate: Administer over 15 min.
  • Y-Site Compatibility: dexamethasone, granisetron, methylprednisolone, ondansetron, palonosetron
  • Solution Incompatibility: Incompatible with solutions containing divalent cations (calcium, magnesium) including LR and Hartmann's solution.

Patient/Family Teaching

  • Instruct patient to take aprepitant as directed. Direct patient to read the Patient Package Insert before starting therapy and to reread it each time the prescription is renewed.
  • Instruct patient to notify health care professional if nausea and vomiting occur prior to administration.
  • Advise patient to notify health care professional immediately if symptoms of hypersensitivity reaction (hives, rash, itching, redness of the face/skin, difficulty in breathing or swallowing) occur.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Caution patient that fosaprepitant may decrease the effectiveness of oral contraceptives. Advise patient to use alternate nonhormonal methods of contraception during and for 1 mo following treatment. Advise patient to notify health care professional if pregnancy is planned or suspected or if breast feeding.
  • Advise patient and family to use general measures to decrease nausea (begin with sips of liquids and small, nongreasy meals; provide oral hygiene; remove noxious stimuli from environment).

Evaluation/Desired Outcomes

  • Decreased nausea and vomiting associated with chemotherapy.
  • Prevention of postoperative nausea and vomiting.

aprepitant

A neurokinin receptor antagonist drug used to prevent the nausea and vomiting, whether current or delayed, associated with cisplatin-based anticancer therapy. Aprepitant is an orally active antagonist of substance P neurokinin-1 receptors and is the first of a new class of antiemetic drugs.