THERAPEUTICS

Brands

• Emend

Generic?

• No

Class

• Antiemetic

Commonly Prescribed for

(FDA approved in bold)

• Prevention of nausea and vomiting (chemotherapy, postoperative)

• Nausea and vomiting (gastroenteritis, pregnancy)

• Pruritus

How the Drug Works

• Selective blocking agent of substance P/ neurokinin 1 (NK1) receptors. No affinity for 5-HT3, dopamine, and corticosteroid receptors. It augments the antiemetic activity of the 5-HT3 antagonist ondansetron and corticosteroid dexamethasone

How Long Until It Works

• Less than an hour

If It Works

• Use at lowest effective dose

If It Doesn't Work

• Increase dose, or discontinue and change to another agent

Best Augmenting Combos for Partial Response or Treatment-Resistance

• May add D2 antagonist, 5-HT3 antagonist, antihistamine, benzodiazepine, or corticosteroid

Tests

• None required

ADVERSE EFFECTS (AEs)

Notable AEs

• Asthenia, diarrhea, hiccup, pruritus, hair loss

Life-Threatening or Dangerous AEs

• Hypersensitivity reactions such as angioedema and Stevens-Johnson syndrome have been reported

Weight Gain

• Unusual

Sedation

• Unusual

What to Do About AEs

• Reduce dose or discontinuation

Best Augmenting Agents to Reduce AEs

• Symptomatic management

DOSING AND USE

Usual Dosage Range

• 40–150 mg

Dosage Forms

• Capsule: 40, 80, 125 mg

• Injection (fosaprepitant dimeglumine): 115, 150 mg

How to Dose

• For chemotherapy-induced nausea/ vomiting: 125 mg 1 hour prior to chemotherapy (day 1) and 80 mg daily (day 2–3), with or without 5-HT3 antagonist and corticosteroid

• For postoperative nausea/vomiting: 40 mg within 3 hours prior to anesthesia induction

Dosing Tips

• Can be taken with or without food. Only for short-term use

Overdose

• May develop drowsiness or headache

Long-Term Use

• Not been studied

Habit Forming

• No

How to Stop

• No need to taper

Pharmacokinetics

• Bioavailability 60–65%. > 95% protein bound. Metabolized predominantly by CYP3A4. Not renally excreted. Half-life 9–12 hours