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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Emend
Generic Name
Aprepitant
Active Ingredient
AprepitantCategory
Substance P/Neurokinin-1 Receptor Antagonist [EPC]
Variants
5
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Emend, you must consult a qualified healthcare professional.
| 80 mg/1 | CAPSULE | ORAL | 0006-0461 |
| KIT | — | 0006-3862 |
Detailed information about Emend
Aprepitant is a potent Substance P/Neurokinin-1 (NK1) receptor antagonist used primarily to prevent chemotherapy-induced and postoperative nausea and vomiting.
The dosage of Aprepitant is strictly dictated by the clinical indication and the specific chemotherapy regimen being used. It is rarely used as a monotherapy (single drug).
For patients receiving highly emetogenic chemotherapy, the standard 3-day regimen is:
Aprepitant is typically given alongside a 5-HT3 antagonist (like Ondansetron) on Day 1 and Dexamethasone on Days 1 through 4.
Aprepitant is approved for use in pediatric patients (6 months of age and older) for the prevention of CINV. The dosing is typically weight-based:
No dosage adjustment is necessary for patients with renal impairment or those with end-stage renal disease (ESRD) undergoing hemodialysis. Because Aprepitant is not significantly cleared by the kidneys, the pharmacokinetic profile remains stable.
Clinical studies have shown that the efficacy and safety of Aprepitant in the elderly (65 years and older) are comparable to younger adults. No specific dose adjustments are required based solely on age, though overall health and other medications must be considered.
If you miss a dose, contact your doctor immediately for instructions. Because Aprepitant is part of a precisely timed regimen, a missed dose can significantly increase the risk of breakthrough nausea. Do not double the dose to catch up unless specifically instructed by your healthcare provider.
In the event of an overdose, symptoms may include extreme drowsiness or a intensified version of common side effects. There is no specific antidote for Aprepitant. If an overdose is suspected, contact a Poison Control Center (1-800-222-1222 in the US) or seek emergency medical attention immediately. Treatment is generally supportive, focusing on managing symptoms and monitoring vital signs.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop the 3-day regimen without medical guidance, even if you do not feel nauseous.
Most patients tolerate Aprepitant well, especially since it is used for a short duration. However, because it is almost always given with chemotherapy and other antiemetics, it can be difficult to distinguish which drug is causing a specific symptom. Common side effects include:
Aprepitant is a powerful modulator of liver enzymes. The most important safety consideration is the potential for interactions with other medications. Patients must provide a complete list of all prescriptions, over-the-counter drugs, and herbal supplements to their oncology team before starting Aprepitant.
No FDA black box warnings for Aprepitant.
Hypersensitivity reactions, including anaphylaxis, have occurred in patients taking Aprepitant. These reactions can occur with the first dose. If you have a known allergy to Aprepitant or Fosaprepitant (the IV version), you must not take this medication. Signs of a reaction include wheezing, chest tightness, and swelling of the throat.
Isolated cases of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) have been reported. These are medical emergencies. If you notice a blistering rash, especially one accompanied by fever or flu-like symptoms, stop the medication and seek emergency care immediately.
Certain drugs must never be used with Aprepitant because the interaction can cause dangerously high levels of the other medication in the bloodstream, potentially leading to fatal heart rhythm problems (QT prolongation).
Absolute contraindications are conditions where the risk of using the drug clearly outweighs any potential benefit. Aprepitant must NEVER be used in the following scenarios:
FDA Pregnancy Category: Not Assigned (The old ABCDE system has been replaced by the Pregnancy and Lactation Labeling Rule).
There are no adequate and well-controlled studies of Aprepitant in pregnant women. Animal studies using doses much higher than the human clinical dose did not show evidence of direct harm to the fetus. However, because animal studies are not always predictive of human response, Aprepitant should be used during pregnancy only if clearly needed. It is especially important to note that Aprepitant can interfere with hormonal birth control, which may lead to unintended pregnancy if back-up methods are not used.
It is not known whether Aprepitant is excreted in human breast milk. However, animal studies have shown that the drug is present in the milk of lactating rats. Because of the potential for serious adverse reactions in a nursing infant, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Most oncology protocols suggest pausing breastfeeding during the 3-day treatment window and for a short period afterward.
Aprepitant is a selective, high-affinity antagonist at the Neurokinin-1 (NK1) receptor. Its primary target is the Substance P neurotransmitter, a member of the tachykinin family. Substance P is found in the vagus nerve afferent fibers and the nucleus tractus solitarius (NTS), which are key components of the brain's emetic center. By binding to the NK1 receptor, Aprepitant prevents Substance P from initiating the signaling cascade that leads to the physical act of vomiting. It has little to no affinity for other receptors involved in emesis, such as 5-HT3, dopamine D2, or muscarinic receptors.
The pharmacodynamics of Aprepitant are characterized by its ability to cross the blood-brain barrier and occupy NK1 receptors in the brain. Positron Emission Tomography (PET) studies in humans have shown that Aprepitant achieves greater than 90% receptor occupancy in the brain at clinical doses. The duration of effect is long enough to support once-daily dosing, which is critical for managing the 'delayed phase' of nausea that occurs days after chemotherapy.
| Parameter | Value |
Common questions about Emend
Aprepitant is primarily used to prevent nausea and vomiting caused by chemotherapy treatments and surgery. It is specifically effective at preventing 'delayed' nausea, which occurs 24 hours or more after a chemotherapy session. Healthcare providers usually prescribe it as part of a multi-drug regimen that includes other anti-nausea medications like ondansetron and dexamethasone. It is not used to treat nausea that you already have, but rather to prevent it from starting. It is approved for both adults and children over 6 months old for chemotherapy-related use.
The most frequently reported side effects include fatigue, hiccups, and gastrointestinal issues like diarrhea or constipation. Many patients also report a temporary loss of appetite or a general feeling of weakness. Because it is usually taken with chemotherapy, it can be hard to tell which symptoms are from Aprepitant and which are from the cancer treatment itself. Most of these side effects are mild and go away once the 3-day treatment course is finished. However, if you experience severe skin rashes or difficulty breathing, you should seek emergency medical care immediately.
While there is no specific chemical reaction between alcohol and Aprepitant, it is generally recommended to avoid alcohol during your treatment. Alcohol can irritate the stomach and increase the likelihood of nausea and vomiting, which Aprepitant is trying to prevent. Additionally, both alcohol and Aprepitant can cause dizziness and strain the liver. Combining them may make you feel significantly more drowsy or lightheaded. Always check with your oncologist before consuming alcohol during any phase of chemotherapy.
The safety of Aprepitant during pregnancy has not been fully established in human studies. Animal studies did not show direct harm to the fetus, but doctors typically only prescribe it if the benefits to the mother outweigh the potential risks to the baby. A major concern for women of childbearing age is that Aprepitant makes hormonal birth control (pills, patches, etc.) less effective. This effect can last for up to a month after the last dose. If you are taking Aprepitant, you must use a back-up method of birth control, like condoms, to prevent pregnancy.
Aprepitant reaches its peak levels in the blood about 4 hours after you take the capsule. However, because it is a preventative medication, it begins working at the receptor level shortly after absorption to block the 'vomit signals' in the brain. This is why it is critical to take the first dose at least one hour before your chemotherapy begins or within three hours before surgery. It provides protection for a full 24 hours, which is why it is dosed once daily during the 3-day regimen. It is designed to stay in your system long enough to cover the period when delayed nausea is most likely to occur.
Aprepitant is typically only taken for three days at a time, so there is no need to 'taper off' the medication. However, you should not skip any of the doses in the 3-day cycle prescribed by your doctor. Stopping the medication early—for example, taking the Day 1 dose but skipping Days 2 and 3—will significantly increase your risk of experiencing severe nausea and vomiting on the days following your chemotherapy. If you are having trouble swallowing the capsules or are experiencing side effects, talk to your doctor before stopping the regimen.
If you miss a dose of Aprepitant, you should contact your doctor or oncology nurse immediately for guidance. Because the timing of this medication is synchronized with your chemotherapy, missing a dose can leave you unprotected against nausea. Do not take two doses at once to make up for a missed one unless your doctor specifically tells you to. Your healthcare team may have a specific protocol for 'rescue' anti-nausea medications if the Aprepitant window is missed. Keep your medication schedule in a visible place to help avoid missed doses.
Weight gain is not a recognized side effect of Aprepitant. In fact, many patients experience a temporary decrease in appetite (anorexia) while taking the medication, which could lead to slight weight loss if it persists. However, Aprepitant is often taken with dexamethasone, a steroid that is well-known for causing increased appetite, fluid retention, and weight gain with prolonged use. If you notice significant changes in your weight, it is more likely related to the other medications in your regimen or the chemotherapy itself rather than the Aprepitant.
Aprepitant has many significant drug interactions because it affects how the liver processes other medicines. It can increase the levels of certain drugs, like some blood thinners, steroids, and chemotherapy agents, making them more toxic. It can also decrease the effectiveness of others, such as birth control pills and warfarin. It is absolutely vital that you tell your doctor about every single medication and supplement you take. Your doctor may need to adjust the doses of your other medications while you are using Aprepitant to ensure safety.
Yes, Aprepitant is available as a generic medication. The generic versions are bioequivalent to the brand-name drug Emend, meaning they work the same way in the body. Generic Aprepitant is usually much more affordable than the brand-name version and is widely covered by most insurance plans. It is available in the same capsule strengths (40mg, 80mg, and 125mg) and is also available as a generic oral suspension for pediatric use. Talk to your pharmacist or doctor if you have questions about switching to the generic version.
Other drugs with the same active ingredient (Aprepitant)
While rare, serious reactions can occur. You must monitor your body closely during the treatment period.
> Warning: Stop taking Aprepitant and call your doctor immediately if you experience any of these:
Aprepitant is typically administered for very short durations (1 to 3 days per chemotherapy cycle). Consequently, long-term side effects are not well-documented in standard clinical use. However, repeated use across many cycles of chemotherapy is generally considered safe, provided liver function is monitored and drug interactions are managed.
There are currently no FDA black box warnings for Aprepitant. However, the FDA does emphasize the critical nature of its drug-drug interactions, particularly with medications metabolized by CYP3A4, which can lead to life-threatening complications if not managed correctly.
Report any unusual symptoms to your healthcare provider. Even mild side effects should be discussed, as your doctor may be able to provide supportive care to manage them.
Aprepitant reduces the effectiveness of hormonal contraceptives (birth control pills, patches, implants, and some IUDs). This effect can last for up to 28 days after the last dose of Aprepitant. Patients of childbearing potential should use a highly effective back-up method of contraception (such as condoms) during treatment and for one full month after the final dose to prevent unintended pregnancy.
For patients on chronic warfarin therapy, Aprepitant can cause a significant decrease in the International Normalized Ratio (INR), which increases the risk of blood clots. This effect is delayed, usually peaking 7 to 10 days after the 3-day Aprepitant regimen is completed.
Healthcare providers typically monitor the following during Aprepitant therapy:
Aprepitant may cause dizziness or fatigue in some patients. You should avoid driving or operating heavy machinery until you know how the medication affects you. This is particularly important because chemotherapy itself often causes significant cognitive 'fog' and exhaustion.
There is no direct chemical interaction between Aprepitant and alcohol. However, alcohol can irritate the stomach lining and worsen nausea or vomiting, which defeats the purpose of the medication. Furthermore, alcohol can increase the risk of dizziness and liver strain. It is generally advised to avoid alcohol during the days you are taking Aprepitant.
There is no known withdrawal syndrome associated with stopping Aprepitant after a 3-day course. Because it is used for short-term prevention, tapering is not required. However, stopping the medication early during a chemotherapy cycle will likely result in a failure to prevent delayed nausea.
> Important: Discuss all your medical conditions, especially liver disease and any history of allergic reactions, with your healthcare provider before starting Aprepitant.
Aprepitant does not have many known interactions with common laboratory tests, but its effect on liver enzymes (ALT/AST) can cause transient elevations that may be misinterpreted if the healthcare provider is unaware of the medication use.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. Even 'natural' products can interfere with how Aprepitant works or cause dangerous side effects.
These are conditions where the drug should be used with extreme caution and only after a thorough risk-benefit analysis by a specialist:
Patients who have had an allergic reaction to Fosaprepitant (the intravenous form) are highly likely to be allergic to Aprepitant, as Fosaprepitant is a prodrug that converts directly into Aprepitant within minutes of injection. There is no known cross-sensitivity between Aprepitant and other classes of antiemetics, such as 5-HT3 antagonists (Ondansetron) or Dopamine antagonists (Metoclopramide).
> Important: Your healthcare provider will evaluate your complete medical history, including all allergies and current heart health, before prescribing Aprepitant.
Aprepitant is approved for the prevention of CINV in pediatric patients as young as 6 months of age.
In clinical trials, no overall differences in safety or effectiveness were observed between subjects 65 years of age and older and younger subjects. However, elderly patients are more likely to have decreased hepatic or cardiac function and are often taking multiple other medications (polypharmacy). Therefore, the risk of drug interactions is significantly higher in this population. Healthcare providers should perform a comprehensive 'brown bag' medication review before prescribing.
Aprepitant is not cleared by the kidneys. Therefore, no dosage adjustment is necessary for patients with any degree of renal impairment, including those on hemodialysis. The drug is not dialyzable, so it can be administered without regard to the timing of dialysis sessions.
> Important: Special populations require individualized medical assessment. Always inform your specialist about your pregnancy status or any history of organ dysfunction.
| Bioavailability | ~60% to 67% |
| Protein Binding | >95% (primarily Albumin) |
| Half-life | 9 to 13 hours |
| Tmax | ~4 hours |
| Metabolism | Hepatic (Primarily CYP3A4; minor CYP1A2, CYP2C19) |
| Excretion | Fecal 86%, Renal 5% |
Aprepitant is the prototypical member of the Substance P/Neurokinin-1 (NK1) Receptor Antagonist class. Related medications include Fosaprepitant (the IV prodrug), Rolapitant, and Netupitant (often sold in combination with palonosetron as Akynzeo). These drugs have transformed oncology by specifically targeting the delayed phase of emesis that was previously difficult to control.