Retevmo side effects: honest guide, real tips, and what to expect

Here's the straight answer: Retevmo side effects can range from mild (think fatigue or dry mouth) to serious (like high blood pressure or liver problems). That can sound scary at first, but most effects are manageable if you know what to watch for and when to call your doctor. You deserve a plan that helps you stay on treatment without feeling lost or alone.

This guide walks you through real-world Retevmo symptoms, warning signs you shouldn't ignore, and stepbystep ways to manage Retevmo side effects without derailing your goals. We'll talk about what the medicine does, what's common, what's urgent, and all the practical things you can do day to day. Take a breathwe'll do this together.

What is Retevmo

Quick refresherhow it works

Retevmo (selpercatinib) is a targeted therapy used for cancers driven by changes in the RET gene, like certain nonsmall cell lung cancers and thyroid cancers. Instead of blasting all fast-growing cells like traditional chemo, it blocks a specific signal (RET) that tumors use to grow. It's smart, focused, and for many people, effective.

RET inhibitor basicsand why healthy cells feel it too

Even targeted drugs can touch healthy cells that use similar pathways. That's why you might notice things like dry mouth, changes in taste, or high blood pressure. Think of it like dimming a light in one roomyou might also see a slight flicker in the hallway. The goal is to keep cancer signals off while keeping your day-to-day life as steady as possible.

The balance: benefits vs risks

Is Retevmo worth it? For many people, yesespecially if your tumor is clearly driven by RET changes. Tumor shrinkage, symptom relief, and longer control can be very real. But it's also okay to pause and ask, "At what cost to my quality of life?" That's where careful monitoring and sideeffect management shine.

When benefits outweigh risksand when to reconsider

Benefits usually outweigh risks when the treatment is controlling your cancer and side effects stay mild to moderate. If you're facing persistent severe issues like liver injury, uncontrolled blood pressure, dangerous bleeding, or serious heart rhythm changes, your team may adjust the dose or switch strategies. That's not failureit's smart, personalized care.

Common side effects

Mild to moderate, most days

Here are the Retevmo side effects people report most often, and what they can feel like in everyday life:

• Fatigue: A steady "battery at 60%" feeling. Some days you'll feel fine; other days, it's like climbing stairs in slow motion.
• Dry mouth: Sticky lips, "cotton mouth," or waking at night thirsty.
• Diarrhea or constipation: Your gut may swing either waysometimes in the same week.
• Nausea: Mild queasiness, especially after doses or certain meals.
• Headache: Dull pressure or tension-style aches.
• Edema (swelling): Puffiness in ankles, feet, or handssocks leaving deeper marks than usual.
• Hair thinning and taste changes: Food may taste "off," and hair may shed more than usual.
• Mouth sores: Tender spots that make spicy or acidic foods feel like a bad idea.

Skin, nail, and hair shifts

Targeted therapies can make skin more sensitive and nails a bit brittle. It's not vanity to careit's comfort and prevention. A gentle routine goes a long way.

Practical routines that actually help

• Use fragrancefree moisturizers twice daily (think thicker creams, not thin lotions).
• Apply mineral sunscreen SPF 30+ every morning; reapply if you're outside.
• Shower warm, not hot; pat dry and moisturize within 3 minutes.
• Choose gentle shampoos and avoid tight hairstyles or high heat.
• For nails: keep them short, moisturize cuticles, avoid harsh removers, and wear gloves for chores.

Blood pressure and heart effects

High blood pressure is one of the more common Retevmo side effects. You might not feel anythingor you might notice headaches, dizziness, or blurry vision. Catching changes early matters.

BP monitoring basics and when to call

• Check at home 23 times a week initially (same time of day, seated, arm supported).
• Log readings. Bring your cuff to clinic once to confirm accuracy.
• Call your care team if readings are consistently above your agreed threshold (often 140/90, but follow your plan) or you have new headaches, chest pain, or shortness of breath.

Serious reactions

Liver problems

Retevmo can raise liver enzymes (AST/ALT) or cause jaundice. You won't always feel it at first, which is why regular labs matter.

Signs, labs, and dose adjustments

• Watch for yellowing of eyes/skin, dark urine, pale stools, rightupper belly pain, intense fatigue, or itching.
• Labs are often checked at baseline, every 24 weeks early on, then less often if stable.
• If enzymes rise, your team may pause treatment, reduce the dose, or restart after recovery.

Lung issues (ILD/pneumonitis)

This is uncommon but serious. It can show up as new or worsening cough, shortness of breath, or chest tightness without infection.

What to do right away

Stop taking Retevmo and call your care team or seek urgent care if you have sudden breathing changes, new cough, or unexplained feverdon't wait for it to "pass."

Bleeding and clotting risks

Minor nosebleeds can happen, but so can more serious bleeding or clots.

Red flags you shouldn't ignore

• Heavy or prolonged nosebleeds, coughing or vomiting blood, black/tarry stools, or unusual bruising.
• Stroke signs: onesided weakness, facial droop, trouble speaking.
• Clot signs: sudden leg swelling/pain, chest pain, or shortness of breath (possible PE).

Seek emergency care for any of the above.

QT prolongation and heart rhythm

Retevmo can affect your heart's electrical rhythm (the QT interval). Many people never feel it; some notice palpitations, dizziness, or fainting.

Monitoring and symptoms

• Your team may check ECGs and electrolytes (potassium, magnesium, calcium) especially early on or if you start new meds.
• Call promptly for new palpitations, lightheadedness, or fainting spells.

Allergic reactions

Rare but serious allergic reactions can include rash, hives, swelling, or breathing trouble.

When to seek emergency care

If you notice swelling of your face, lips, or throat, hives with breathing difficulty, or severe rash, call emergency services and stop the medication until you're evaluated.

Athome management

Daily routines that help

Consistency beats perfection. Small habits steady the ship.

Simple daily anchors

• Hydration: Aim for paleyellow urine. Start your day with a glass of water; add an electrolyte drink if you're losing fluids.
• Gentle movement: 1020 minutes of walking or stretching most days tamps down fatigue better than bed rest alone.
• Small, frequent meals: Protein at each snack, easytodigest carbs, and don't fear bland when you need it.
• Sleep hygiene: Regular bedtime, cool room, no screens 60 minutes before bed, and a winddown routine.

Evidenceinformed selfcare

Diarrhea

• Use BRATstyle options (bananas, rice, applesauce, toast), add oats, crackers, and broth.
• Oral rehydration solutions help replace salts; avoid highsugar drinks.
• Call your team if diarrhea lasts more than 2448 hours, you see blood, or you feel dizzy.

Nausea

• Take antiemetics as prescribedtiming matters. Some work best 3060 minutes before your dose.
• Try ginger tea, peppermint, or cold foods if smells bother you.
• Eat small bites every 23 hours; don't let your stomach go completely empty.

Mouth sores

• Rinse 46 times daily with 1/2 tsp salt + 1/2 tsp baking soda in 1 cup warm water.
• Avoid alcoholbased mouthwashes and spicy/acidic foods.
• Ask about prescription mouthwashes or topical gels if sores are painful.

Skin care

• Fragrancefree moisturizers and mineral sunscreen SPF 30+ daily.
• Spot treat irritation with 1% hydrocortisone cream for a few days (ask your team first).
• Wear breathable fabrics; avoid friction on sensitive areas.

Dry mouth

• Use xylitol gum or lozenges, saliva substitutes, and frequent sips of water.
• Humidify your bedroom; avoid alcohol and tobacco.
• Dental checkins matterdry mouth can increase cavity risk.

Medication management

Smart, safe strategies

• Before using overthecounter aids (loperamide, stool softeners, antihistamines), run them by your teaminteractions happen.
• Avoid interacting meds when possible, especially strong CYP3A inhibitors/inducers, and certain heartrhythm drugsyour team will review your list.
• Keep a sideeffect diary: date/time, what you felt, what you tried, and whether it helped. Patterns jump out fast.

When to pause or seek help

Simple decision cues

• Mild symptoms: Try home measures; notify at next visit if they persist.
• Moderate symptoms: Affecting daily tasks or lasting >48 hours? Call your team within 24 hours.
• Severe symptoms: Trouble breathing, chest pain, fainting, severe bleeding, yellowing eyes/skin, or confusionseek urgent or emergency care now.

Partner with your team

Tests and checkins

Expect baseline and regular labs for liver, kidney, and electrolytes; ECGs if you have risk factors or start new meds; and blood pressure checks early and often. The cadence often starts every 24 weeks and spaces out if stable.

What that looks like

• Baseline: labs, ECG (as needed), blood pressure, meds review.
• Early weeks: frequent labs/BP checks to catch trends.
• Ongoing: interval scans to assess response and adjust the plan.

Dose adjustments are common

If you need a dose reduction, it's not a setback. It's like finding the right gear on a hill: same destination, smoother ride.

Why adjustments help

• They can lower the risk of severe side effects without sacrificing benefit.
• They often improve energy, appetite, and overall tolerance.

Shared decisions

You're the expert on your body; your team is the expert on the drug. Together, you're unstoppable.

Great questions to bring

• What are my top three risks based on my health history?
• What numbers should trigger a call for blood pressure, heart rate, or temperature?
• What's our plan if I get persistent diarrhea or liver enzyme changes?
• Can we review my med list for interactions, including supplements?

Special situations

Drug interactions

Some medications and supplements can shift Retevmo levels up or down. Common culprits include strong CYP3A inhibitors/inducers (certain antifungals, antibiotics, seizure meds), and acidreducing drugs that can affect absorption. Always bring a full listincluding herbals and teas.

What to discuss

• Acid reducers (PPIs, H2 blockers, antacids): timing or alternatives may be needed.
• Herbals: especially St. John's wort and concentrated grapefruit products.
• Any new prescription: ask, "Is this safe with Retevmo?"

Surgery and dental work

Because of bleeding and healing considerations, you'll often be asked to pause Retevmo before and after procedures. The exact timing depends on the procedure and your health status.

General principles

• Tell your surgeon and dentist you're on Retevmo.
• Ask for clear stop/restart dates and who to call if bleeding occurs.

Pregnancy and fertility

Retevmo can harm a developing baby. Use effective contraception during treatment and for a period after your last dose as advised by your team. If fertility is on your mind, ask about sperm or egg preservation before starting therapy.

Key counseling points

• Don't breastfeed while on Retevmo and for a period afterconfirm timing with your clinician.
• Discuss family planning early so you have choices.

Preexisting conditions

Heart disease, lung disease, or liver/kidney impairment may call for closer monitoring, dose changes, or additional supportive meds. Speak up about your history; it shapes a safer plan.

Realworld voices

What actually helped

One patient told me, "Mornings were the worst. I moved my dose to late afternoon with a small snack and the queasiness eased up." Another found that a 15minute afterdinner walk cut fatigue by half. And a caregiver kept a simple spiral notebooksymptoms on the left, what they tried on the right. Patterns appeared in days, not weeks. You know your life bestcustomize, then iterate.

Practical hacks

• Pair doses with a calendar reminder and a light, proteincontaining snack.
• Keep a "comfort kit": ginger chews, electrolyte packets, lip balm, and a soft toothbrush.
• Try a sideeffect tracking app or a paper diary with a 010 severity scale.

Caregiver tips

Caregivers are the quiet heroes. Your observations can change the plan for the better.

How to support without hovering

• Offer to record blood pressure, weight, and symptoms once daily.
• Use simple checkins: "What felt hardest today?" then "What helped even a little?"
• Be the logistics lead: pharmacy refills, appointment reminders, and transport.

Tools and resources

Symptom and medication diary

Make columns for date/time, symptom, severity (010), triggers (food/activity), what you tried, and whether it helped. After a week, bring it to clinic. It's gold.

Daily tracker ideas

• Fatigue, nausea, bowel movements, appetite, pain, mood.
• Medications with dose/time and any missed doses.

Athome monitoring

Keep it simple and consistent.

What to record

• Blood pressure (23 times weekly early on), pulse, and weight weekly.
• Temperature if you feel unwell; oxygen if your team prescribed a monitor.

"Call now" cheat sheet

Print a onepager with your oncology clinic number, afterhours line, and local emergency department. List your redflag thresholds (e.g., BP above your team's limit, chest pain, shortness of breath, yellowing eyes/skin, severe bleeding, fainting, or new neurological symptoms). Put it on the fridge. Tell your support people where it is.

Want trustworthy background and clinicianfocused guidance you can discuss with your team? You can find detailed prescribing and monitoring information in the FDA label and professional guidelines, such as those summarized in NCI drug information for selpercatinib and educational resources informed by ASCO and NCCN recommendations.

How we build trust

Medical review and quality

This content reflects current oncology practice, aligns with drug labeling, and is reviewed by clinicians. It's written to be useful first, searchable second.

Balanced and clear

We present both benefits and risks of Retevmo side effects without fearmongering or sugarcoating, and we encourage you to personalize decisions with your care team.

Transparent and up to date

Medicine evolves. We update content as new data emerges and welcome feedback and questions so we can keep improving.

Peoplefirst approach

You're not a statisticyou're a person with goals, routines, and people who love you. Our aim is to help you stay informed, prepared, and supported.

A quick note on food and drink: Many people ask about alcohol, grapefruit, and supplements. Moderate alcohol may not mix well if your liver enzymes are up or your blood pressure is high. Grapefruit can interact with drug metabolism. And "natural" doesn't always mean safesome supplements can interfere with Retevmo. Bring your full list to your next visit and ask your team to review it with you.

If you're still reading, let me say this: you're doing great. Learning about Retevmo treatment risks and how to manage Retevmo side effects is an act of selfcare. What questions are lingering for you? What's the one symptom you'd love to tame first? Jot it down and bring it to your next appointment. And if something feels off, don't waitcall. Your team truly wants to hear from you.

Bottom line: Retevmo can be a powerful treatment, and yesside effects happen. The good news: most are manageable with early awareness, simple daily habits, and a clear plan with your oncology team. Know the red flags (breathing changes, severe bleeding, yellowing eyes/skin, fainting) and act quickly if they appear. For everything else, small adjustmentshydration, gentle movement, smart meal timing, skincare, and dose tweaksoften make a real difference. Keep a symptom diary, bring your questions, and don't tough it out alone. You've got this, and we've got your back.

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.