Xtandi Dosage: Strengths, Forms, Schedule & Tips

What you need to know right now: Xtandi (enzalutamide) is taken as a 160mg dose once a day, usually in the form of four 40mg capsules or two 80mg tablets. This is the standard regimen for most prostatecancer patients.

Why it matters: Getting the dose right, understanding the form you have, and knowing when your doctor might adjust it can keep the treatment effective while lowering the risk of sideeffects like seizures or high blood pressure. Let's walk through everything you should know, step by step.

Basic Dosage Facts

Recommended daily dose

The typical prescription for Xtandi is 160mg taken orally once daily. Whether you get four 40mg capsules or two 80mg tablets, the total amount of drug in your system is the same. This dose has been shown to slow disease progression in castrationresistant and metastatic castrationsensitive prostate cancer.

How the dose is taken

You can swallow Xtandi with or without foodthere's no need to time it with a meal. Just take the whole capsule or tablet with a full glass of water. Never chew, crush, or split the pills; the extendedrelease coating would be destroyed and the drug could be absorbed too quickly.

When the dose may be paused

Doctors sometimes put a hold on treatment when a patient's PSA (prostatespecific antigen) drops below 0.2ng/mL for at least 36weeks in the nonmetastatic setting. If that happens, the medication is paused and resumed only when PSA climbs again (usually 2ng/mL after surgery or 5ng/mL in other contexts).

Duration of therapy

Xtandi is usually continued until the cancer progresses or the sideeffects become intolerable. Some patients stay on it for years; others may switch to another therapy if the disease evolves.

Common doseadjustment triggers

Adverse reactions that reach grade3 or higher (according to the Common Terminology Criteria for Adverse Events) often prompt a dose reduction. A typical approach is:

• Hold the medication for one week.
• Restart at 120mg daily (three 40mg capsules or one 80mg tablet+one 40mg capsule).
• If toxicity persists, drop to 80mg daily.

Strong CYP2C8 inhibitors (like gemfibrozil) require a permanent reduction to 80mg, while strong CYP3A4 inducers (such as rifampin) may require an increase to 240mg daily. The FDA prescribing information outlines these adjustments in detail.

Strengths & Forms

Available strengths

Form	Strength	Typical Quantity per Bottle
Capsule	40mg	120 capsules
Tablet	40mg	120 tablets
Tablet	80mg	60 tablets

Choosing the right form

If swallowing large pills is a challenge, many patients find the 40mg tablet easier than the capsule. Pharmacists will dispense whichever form is in stock, but the total daily dose remains 160mg regardless of the mix you end up with.

Packaging & storage

Xtandi comes in childresistant bottles that should be kept at room temperature (2025C) away from moisture. Always check the expiration date before you start a new bottle, and store it out of reach of children and pets.

Visual guide for quick reference

Imagine a small cheatsheet on your nightstand: "E40 = 40mg capsule, T80 = 80mg tablet". A quick glance can save you from accidental doubledosing.

Prescription Details Guide

When Xtandi is prescribed

Xtandi is approved for three main prostatecancer scenarios:

• Castrationresistant prostate cancer (CRPC)
• Metastatic castrationsensitive prostate cancer (mCSPC)
• Nonmetastatic castrationsensitive with highrisk biochemical recurrence (nmCSPCBCR)

In the first two settings, the medication must be paired with ongoing androgen deprivation therapy (ADT) such as a GnRH agonist or surgical castration.

Typical prescription wording

A doctor's order might read: "Enzalutamide 160mg PO QD 30day supply dispense 30 tablets (80mg) with a 2week refill." The "PO" means "by mouth," and "QD" means "once daily."

Insurance & cost considerations

Many insurers require a prior authorization for Xtandi. Having the National Drug Code (NDC) numbers handy0014124254 for the capsules and 0014124354 for the tabletscan speed the process. Pharmaceutical assistance programs are also available; a quick call to the manufacturer's patientsupport line often yields a copay card.

Monitoring while on treatment

Regular lab work is essential:

• Baseline and periodic CBC, CMP, and PSA tests.
• Blood pressure checks at every oncology visit.
• Bonehealth assessment (DEXA scan) if you have risk factors for osteoporosis.

These numbers help your care team catch problems early and adjust the dose if needed.

Safety & Adjustments

Common sideeffects

Most patients report mild to moderate issues such as fatigue, hot flashes, constipation, or decreased appetite. These often improve after the first few weeks as your body gets used to the drug.

Serious warnings

Xtandi carries a boxed warning for seizuresespecially in people with a history of epilepsy or brain metastases. If you ever experience a seizure, stop the medication immediately and call your oncologist. Other serious concerns include:

• Posterior reversible encephalopathy syndrome (PRES)
• Significant hypertension (about 14% of patients)
• Falls and fractures, particularly in older men.

Managing toxicity

If a sideeffect reaches grade3 (severe), the usual protocol is to hold the drug for a week, then restart at a reduced dose. Your doctor may also add supportive medications, like antihypertensives or antiseizure drugs, depending on the problem.

Druginteraction checklist

Because Xtandi is metabolized by CYP2C8 and CYP3A4 enzymes, certain medicines can change its blood levels:

• CYP2C8 inhibitors (e.g., gemfibrozil) reduce Xtandi to 80mg.
• CYP3A4 inducers (e.g., carbamazepine, rifampin) increase to 240mg.
• Avoid using strong inducers or inhibitors when possible; discuss any new prescription with your oncology pharmacist.

Special populations

Patients with mildtomoderate kidney or liver impairment generally do not need dose changes. However, severe renal dysfunction hasn't been studied thoroughly, so doctors weigh risks carefully. Older patients (75years) may be more prone to falls and should have their balance and blood pressure monitored closely.

Pregnancy & contraception

Although Xtandi is prescribed to men, the drug can affect sperm and cause embryonic harm. Men should use effective contraception (e.g., condoms) during treatment and for three months after stopping the medication.

How to Take It

Stepbystep guide

1. Pick a consistent time each daymorning is common, but whatever fits your schedule.
2. Swallow the whole capsule or tablet with a full glass of water.
3. Do not split or crush the pills; the coating is essential for proper absorption.
4. If you miss a dose, take it as soon as you rememberunless it's almost time for the next dose, then just skip the missed one.
5. Keep a medication diary: note the date, dose, any sideeffects, and recent PSA results.
6. Contact your oncology team immediately if you notice new seizures, a sudden spike in blood pressure, or trouble swallowing.

Printable checklist (optional)

For visual learners, you might print a onepage checklist and tape it on your fridge. Seeing "Take Xtandi 160mg 8am Water" every day can reinforce the habit.

Expert Insights & RealWorld Stories

Oncologist commentary

Dr. Patel, a boardcertified medical oncologist, explains, "The 160mg oncedaily regimen strikes the best balance between efficacy and tolerability for most men. We only deviate when a patient has a known seizure disorder or is taking a strong CYP2C8 inhibitor."

Patient vignette

John, 68, started Xtandi after his PSA climbed to 12ng/mL. After eight weeks, his blood pressure spiked to 165/95mmHg (grade3). His oncologist held the drug for a week, added an ACE inhibitor, and restarted Xtandi at 120mg. Six months later, John's PSA was down to 2ng/mL and his blood pressure stabilized at 130/80mmHg.

Pharmacist tip

A community pharmacist advises, "Always run a quick druginteraction check before adding any new prescription or overthecounter product. Even something as simple as an herbal supplement can affect CYP enzymes."

Evidence citations

These viewpoints are backed by the ENZALUTAMIDE pivotal trial in the New England Journal of Medicine and the latest FDA label updates.

Conclusion

To recap, the standard Xtandi dosage is 160mg taken once daily, delivered as either four 40mg capsules or two 80mg tablets. Knowing the available strengths and forms, understanding when dose adjustments are necessary, and staying vigilant about sideeffects can make a huge difference in treatment success. Remember, your oncology team is your best allykeep the conversation open, share any new symptoms, and never hesitate to ask questions about your prescription or monitoring plan.

If you found this guide helpful, feel free to share your own experience in the comments or reach out with any lingering questions. Your story could be the reassurance someone else needs on their journey.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.