Lonsurf 20 Mg Tablets

Comprehensive Guide to Lonsurf 20mg Tablets (Trifluridine and Tipiracil)

Lonsurf 20mg is a prescription oral combination chemotherapy medication utilized in advanced clinical oncology. Manufactured by Taiho Oncology, Inc., each tablet contains two active pharmaceutical ingredients: trifluridine and tipiracil (as tipiracil hydrochloride).

Lonsurf is designed for adult patients with advanced gastrointestinal cancers that have progressed following prior standard therapies. Rather than acting like a single chemical agent, Lonsurf combines a DNA-disrupting antimetabolite with a protective enzyme inhibitor to slow down tumor growth and extension.

What is Lonsurf and How Does It Work?

Lonsurf works through a two-part targeted biochemical mechanism:

1. Trifluridine (Cytotoxic Antimetabolite): Trifluridine is a nucleoside metabolic inhibitor. When rapidly dividing cancer cells attempt to build and repair their DNA, they mistakenly incorporate trifluridine into their genetic structure. This direct incorporation damages DNA strands, prevents further tumor cell replication, and leads to cell death (apoptosis).

2. Tipiracil (Enzymatic Protector): If taken alone, trifluridine is rapidly broken down and degraded in the digestive tract and liver by an enzyme called thymidine phosphorylase. Tipiracil acts as a thymidine phosphorylase inhibitor. By blocking this enzyme, tipiracil allows trifluridine to stay intact and reach effective concentrations in the bloodstream and tumor tissues.

[Trifluridine] ---> (Attacks & Destroys Cancer Cell DNA)
       +
[Tipiracil]    ---> (Blocks Degradation Enzymes) = Sustained Anti-Cancer Efficacy

Approved Indications

Lonsurf is indicated for the treatment of adult patients with specific advanced gastrointestinal cancers:

• Metastatic Colorectal Cancer (mCRC): Used as a single agent or in combination with bevacizumab for patients with metastatic colorectal cancer who have previously received fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, an anti-VEGF biological therapy, and (if RAS wild-type) an anti-EGFR therapy.

• Metastatic Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma: Prescribed for adult patients with metastatic gastric or gastroesophageal junction cancer previously treated with at least two prior lines of chemotherapy that included a fluoropyrimidine, a platinum, and either a taxane or irinotecan (plus HER2/neu-targeted therapy if appropriate).

Standard Dosage and Administration Protocols

Lonsurf dosing is calculated based on a patient’s Body Surface Area (BSA) and follows a specific 28-day cyclic schedule.

The 28-Day Treatment Cycle

The standard starting dose is 35 mg/m² twice daily (up to a maximum of 80 mg per single dose), taken as follows:

• Days 1 through 5: Take your prescribed morning and evening doses.

• Days 6 and 7: Rest days (no Lonsurf).

• Days 8 through 12: Take your prescribed morning and evening doses.

• Days 13 through 28: Rest period (no Lonsurf for 14 consecutive days).

This 28-day cycle is repeated as directed by your oncologist until disease progression or unacceptable toxicity occurs.

Essential Administration Rules

• Take with Food: Take Lonsurf within 1 hour after completing your morning and evening meals. Taking it with food helps your body absorb the medicine consistently.

• Swallow Whole: Swallow tablets whole with a full glass of water. Do not chew, crush, split, or dissolve the tablets.

• Tablet Combinations: Lonsurf comes in 15mg and 20mg strengths. Your oncologist may prescribe a combination of both strengths to equal your total required dose.

• Vomited or Missed Doses: If you vomit or miss a scheduled dose, do not take an extra dose. Skip that dose and take your next regularly scheduled dose at the normal time.

Potential Side Effects and Management

Because Lonsurf affects rapidly dividing cells, regular monitoring is necessary to catch and handle complications early.

Common Side Effects

• Gastrointestinal Symptoms: Nausea, vomiting, diarrhea, loss of appetite, abdominal pain, or mild mouth sores.

• Constitutional Symptoms: Unusual fatigue, extreme tiredness (asthenia), low energy, or mild fever.

Serious Adverse Reactions (Seek Immediate Medical Care)

• Severe Myelosuppression (Bone Marrow Suppression): Lonsurf significantly lowers blood cell counts:

  • Neutropenia (Low White Blood Cells): Increases risk for severe infections. Report fever (100.4°F / 38°C or higher), chills, or sore throat immediately.

  • Anemia (Low Red Blood Cells): Causes pale skin, severe fatigue, weakness, or shortness of breath.

  • Thrombocytopenia (Low Platelets): Causes unusual bruising, nosebleeds, bleeding gums, or dark/tarry stools.

• Severe Dehydration: Prolonged diarrhea or vomiting can lead to fluid imbalances and kidney stress.

Clinical Baseline & Routine Testing

To ensure safety throughout therapy, your oncology team will conduct regular clinical tests.

Safe Handling, Storage, and Precautions

• Cytotoxic Handling Precautions: Lonsurf is a cytotoxic oral chemotherapy agent. Caregivers should wear disposable gloves when handling the tablets to prevent direct skin contact. Wash hands thoroughly after handling.

• Storage Conditions: Store Lonsurf in its original bottle at room temperature between 20°C and 25°C (68°F to 77°F). Keep the desiccant packet inside the bottle to protect tablets from moisture.

• 30-Day Expiration Outside Container: If tablets are removed from their original bottle (such as into a pillbox), any unused tablets must be discarded after 30 days.

• Pregnancy & Contraception Warnings:

  • Females: Can cause fetal harm. Females of reproductive potential must verify a negative pregnancy test before starting treatment and use effective contraception during treatment and for at least 6 months after the final dose.

  • Males: Male patients with female partners of reproductive potential must use condoms during treatment and for at least 3 months after the final dose.

  • Lactation: Do not breastfeed during Lonsurf treatment and for at least 1 day after the final dose.

Frequently Asked Questions (FAQs)

Q1: What should I do if my doctor prescribes both 15mg and 20mg tablets together?

It is common to receive two different tablet strengths to reach your exact calculated dose based on your Body Surface Area. Pay close attention to your prescription labels and organize your morning and evening doses carefully—for example, taking one 20mg tablet and one 15mg tablet together if your single dose is 35mg.

Q2: Can I take Lonsurf on an empty stomach?

No. Lonsurf must be taken within 1 hour after finishing your morning and evening meals. Taking it with food ensures consistent drug absorption and reduces nausea.

Q3: What happens if my white blood cell counts drop too low during a cycle?

If your blood counts drop below safe levels (e.g., severe neutropenia), your oncologist may briefly delay your next 28-day cycle or reduce your daily dose for subsequent cycles to allow your bone marrow time to recover.

Medical Disclaimer

This guide is intended strictly for educational and informational purposes and should not replace professional medical advice, diagnosis, or treatment. Always consult a qualified oncologist or healthcare professional before starting, stopping, or altering any chemotherapy regimen.

References

1. National Center for Biotechnology Information (NCBI):

   • StatPearls Review: Trifluridine and Tipiracil Pharmacology & Clinical Applications. https://www.ncbi.nlm.nih.gov/books/NBK560662/

   • PMC Clinical Studies: Trifluridine/tipiracil in metastatic colorectal and gastric cancer management. https://pmc.ncbi.nlm.nih.gov/articles/PMC6637370/

2. U.S. Food and Drug Administration (FDA):

   • LONSURF (trifluridine and tipiracil) Full Prescribing Information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/207981s012lbl.pdf

3. MedlinePlus Drug Information (US National Library of Medicine):

   • Trifluridine and Tipiracil Monograph. https://medlineplus.gov/druginfo/meds/a615053.html

4. Drugs.com Database:

   • Lonsurf Uses, Dosing, Side Effects, and Warnings. https://www.drugs.com/lonsurf.html