Lonsurf (Trifluridine plus Tipiracil) FAQs

Lonsurf (trifluridine and tipiracil) is an oral chemotherapy medication used to treat advanced colorectal cancer and gastric cancer. It is a combination drug that contains two active ingredients:

• Trifluridine: A nucleoside analog that interferes with DNA synthesis in cancer cells
• Tipiracil: A thymidine phosphorylase inhibitor that prevents the breakdown of trifluridine, allowing it to work longer in the body

FDA-Approved Uses:

• Metastatic colorectal cancer (mCRC) in patients who have been previously treated with fluoropyrimidine, oxaliplatin, and irinotecan-based chemotherapy, an anti-VEGF therapy, and if RAS wild-type, an anti-EGFR therapy
• Metastatic gastric cancer or gastroesophageal junction adenocarcinoma in patients previously treated with at least two prior lines of chemotherapy

Yes, Lonsurf (trifluridine and tipiracil) is a type of chemotherapy. It is an oral chemotherapy drug used to treat:

• Metastatic colorectal cancer (that has progressed after standard treatments)
• Metastatic gastric cancer (including gastroesophageal junction cancer)

ablet Strengths:

• 15 mg trifluridine / 6.14 mg tipiracil
• 20 mg trifluridine / 8.19 mg tipiracil

Standard Dosing: The recommended dose is 35 mg/m² (based on body surface area) taken orally twice daily with food on Days 1 through 5 and Days 8 through 12 of each 28-day cycle.

Dose Adjustments: Your oncologist may adjust your dose based on:

• Body surface area (BSA)
• Side effects or toxicity
• Blood cell counts
• Kidney or liver function

Important: Never adjust your dose without consulting your healthcare provider. Take Lonsurf exactly as prescribed.

As of October 2025, there is no generic version of Lonsurf available in the United States. Lonsurf is still under patent protection. However, financial assistance programs exist to help patients afford this medication.

Lonsurf (Trifluridine plus Tipiracil) can cause several potential side effects. Common side effects may include fatigue, nausea, vomiting, diarrhea, decreased appetite, abdominal pain, and anemia. Additionally, patients may experience infections, fever, weakness, headache, dizziness, and changes in blood cell counts. It’s essential to discuss any side effects with a healthcare professional while undergoing treatment with Lonsurf. Here’s a list of some side effects for easy reference;

Common Side Effects:

• Fatigue
• Nausea
• Vomiting
• Decreased appetite
• Diarrhea
• Abdominal pain
• Fever
• Weakness

Serious Side Effects:

• Low White Blood Cell Count (Neutropenia) – Increased risk of infections
• Low Red Blood Cell Count (Anemia) – Fatigue, dizziness, shortness of breath
• Low Platelet Count (Thrombocytopenia) – Increased risk of bleeding and bruising
• Severe Diarrhea – Can lead to dehydration
• Liver Enzyme Elevations – Possible liver damage
• Severe Nausea & Vomiting – Can lead to dehydration and weight loss

Rare but Serious Side Effects:

• Interstitial Lung Disease (ILD) – Inflammation in the lungs causing breathing difficulties
• Severe Allergic Reactions – Rash, swelling, difficulty breathing
• Heart Problems – Chest pain, irregular heartbeat

Patients should inform their doctor if they experience any of these side effects. Some may require immediate medical attention.

Foods to Avoid or Limit:

Grapefruit and Grapefruit Juice

• May interfere with how your body processes certain medications
• Avoid entirely while on chemotherapy unless approved by your doctor

Raw or Undercooked Foods

• Raw fish (sushi, sashimi)
• Raw or undercooked eggs
• Unpasteurized dairy products
• Raw or undercooked meat and poultry
• Why: Lonsurf lowers your white blood cell count, increasing infection risk

Unwashed Fresh Fruits and Vegetables

• Always wash thoroughly or peel before eating
• Avoid pre-cut fruits and vegetables from stores

High-Risk Foods During Low White Blood Cell Counts:

• Deli meats and cold cuts (unless heated to steaming)
• Soft cheeses (brie, feta, blue cheese)
• Buffet or self-serve foods
• Street vendor foods

Drinks to Avoid:

Alcohol

• Can worsen nausea, vomiting, and diarrhea
• May increase liver toxicity risk
• Discuss any alcohol consumption with your doctor

Excessive Caffeine

• May worsen dehydration if you have diarrhea
• Can increase nausea in some patients

General Dietary Recommendations:

DO:

• Take Lonsurf with food (within 1 hour after completing morning and evening meals)
• Stay well-hydrated (8 to 10 glasses of water daily unless restricted)
• Eat small, frequent meals if you have nausea
• Choose bland, easy to digest foods if experiencing GI upset
• Maintain good food safety practices

DON’T:

• Skip meals when taking Lonsurf (food improves absorption)
• Eat spicy or greasy foods if experiencing nausea or diarrhea
• Use expired foods
• Share food or drinks with others when immune system is compromised

Do NOT take Lonsurf if you:

Have a known severe hypersensitivity (allergic reaction) to trifluridine, tipiracil, or any components of Lonsurf

• Previous severe allergic reactions to the medication
• Symptoms like rash, hives, swelling, severe itching, or difficulty breathing

Use with Caution or Inform Your Doctor if You Have:

Bone Marrow Suppression

• Low blood cell counts before starting treatment
• History of blood disorders

Kidney Problems

• Chronic kidney disease
• Reduced kidney function
• Your doctor may need to adjust your dose

Liver Disease

• Hepatitis
• Cirrhosis
• Elevated liver enzymes
• Monitoring may be needed

Pregnancy or Planning to Become Pregnant

• Lonsurf can harm an unborn baby (Pregnancy Category D)
• Use effective birth control during treatment and for 6 months after
• Both men and women should use contraception

Breastfeeding

• It is not known if Lonsurf passes into breast milk
• Do not breastfeed during treatment and for 1 day after the last dose

Recent or Planned Surgery

• Lonsurf can affect healing and increase bleeding risk
• Inform your surgeon you are taking this medication

Active Infections

• May worsen due to lowered immune response
• All infections should be treated before starting Lonsurf

Heart Disease

• History of heart problems
• Irregular heartbeat
• Chest pain

Lung Disease

• History of lung problems or breathing difficulties
• Lonsurf can rarely cause interstitial lung disease

Age Considerations:

Elderly Patients (65+)

• May experience more side effects
• Closer monitoring may be needed
• Dose adjustments may be required

Pediatric Patients

• Safety and effectiveness in children have not been established
• Not recommended for use in pediatric patients

If you miss a dose of Lonsurf:

1. Within 12 hours of scheduled time: Take the missed dose as soon as you remember, with food
2. More than 12 hours late: Skip the missed dose and take your next dose at the regular scheduled time
3. DO NOT take two doses at the same time to make up for a missed dose
4. Call your healthcare provider if you are unsure what to do

If you vomit after taking a dose:

• Do NOT take another dose
• Wait until your next scheduled dose
• Notify your healthcare team if vomiting continues

Seek emergency medical attention or call the Poison Help line immediately at 1-800-222-1222.

Signs of Overdose May Include:

• Severe nausea and vomiting
• Severe diarrhea
• Extreme fatigue or weakness
• Unusual bleeding or bruising
• Signs of infection (fever, chills)
• Difficulty breathing
• Confusion or altered mental state

Emergency Steps:

1. Call 911 or go to the nearest emergency room
2. Bring your medication bottle with you
3. Tell medical staff exactly how much you took and when

Medical Treatment: There is no specific antidote for Lonsurf overdose. Treatment is supportive and may include:

• Blood cell count monitoring
• Hospitalization for severe symptoms
• Supportive care for dehydration
• Treatment of infections if white blood cells are very low
• Blood transfusions if needed

Storage Instructions:

• Store at room temperature between 68 degrees F to 77 degrees F (20 degrees C to 25 degrees C)
• Keep in original bottle with desiccant (moisture absorber) inside
• Keep bottle tightly closed
• Protect from light and moisture
• Do not remove desiccant from bottle

Keep Out of Reach:

• Store away from children and pets
• This medication can be harmful if taken by someone it wasn’t prescribed for

Do Not Use:

• After expiration date on the bottle
• If tablets appear damaged, discolored, or crumbling

Safe Disposal:

• Do not flush down toilet or pour down drain
• Use a drug take-back program or pharmacy disposal service
• If no take-back program available, mix with undesirable substance (coffee grounds, cat litter) in a sealed bag before throwing in trash

Many patients continue working during Lonsurf treatment, but it depends on:

• How you tolerate side effects (especially fatigue)
• Your job’s physical demands
• Your blood cell counts
• Your employer’s flexibility

Tips for Working During Treatment:

• Discuss work limitations with your doctor
• Consider reduced hours or modified duties during treatment cycles
• Take advantage of FMLA (Family Medical Leave Act) if needed
• Avoid high-risk exposure to infections if your white blood cell count is low
• Stay home if you have fever or feel unwell

How effective is Lonsurf for colorectal cancer?

Clinical trials have shown that Lonsurf improves survival in patients with metastatic colorectal cancer who have already received multiple lines of treatment:

RECOURSE Trial Results:

• Median overall survival: 7.1 months with Lonsurf vs. 5.3 months with placebo
• Progression-free survival: 2.0 months with Lonsurf vs. 1.7 months with placebo

While these improvements may seem modest, for patients with advanced cancer who have exhausted other options, Lonsurf can provide meaningful additional time and help control disease progression.

Effectiveness varies by patient. Your oncologist will monitor your response through imaging and tumor markers.

Source: Mayer RJ, et al. Randomized trial of TAS-102 for refractory metastatic colorectal cancer. N Engl J Med. 2015;372:1909-1919. https://www.nejm.org/doi/full/10.1056/NEJMoa1414325

Most insurance plans cover Lonsurf, but it’s typically classified as a specialty medication, which means:

Commercial Insurance:

• Usually covered with prior authorization
• Placed on specialty tier (Tier 4 to 5)
• Copays range from $500 to $3,000 or more per month
• Deductibles must be met first

Medicare Part D:

• Covered under most plans
• Requires prior authorization
• Copays vary by plan
• Good News: The 2025 Medicare cap limits out-of-pocket costs to $2,000 per yearar

Medicaid:

• Typically covered with prior authorization
• Low or $0 copays in most states

Prior Authorization Usually Required: Your oncologist must provide documentation showing:

• Previous treatment history
• Medical necessity
• Disease progression despite prior therapies