Alpelisib side effects — what to expect and how to handle them

Starting alpelisib (brand name Piqray) can feel stressful. It works for certain PIK3CA‑mutated breast cancers, but it can cause side effects you should know about. Below I’ll list the common problems, simple steps you can take at home, and clear signs that mean you need urgent help.

Common side effects and practical fixes

Here are the issues patients most often see and easy ways to deal with them:

• High blood sugar (hyperglycemia) — This is the one doctors worry about most. Check fasting blood sugar before treatment starts and keep testing at home if advised. Mild rises can often be managed with diet changes and medicine like metformin. If you get extreme thirst, peeing a lot, or confusion, get medical help fast.
• Skin rash — Rashes range from mild redness to more serious reactions. Use gentle skin care, sunscreen, and an over‑the‑counter antihistamine for itch. Your doctor may prescribe topical steroids or pause treatment for severe rash.
• Diarrhea, nausea, stomach upset — Drink small amounts of clear fluids, try bland foods, and use loperamide or an anti‑nausea drug if recommended. Call your care team if diarrhea is severe or doesn’t stop after 24–48 hours.
• Fatigue and low appetite — Rest, short walks if you can, and small frequent meals help. Talk to your team about nutritional support if you’re losing weight.
• Elevated liver tests — Your doctor will check liver enzymes regularly. If they jump, treatment may be paused until levels drop.
• Low blood counts (neutropenia) — Your blood will be monitored. Report fevers or signs of infection right away.
• Lung inflammation (pneumonitis) — Shortness of breath or new cough should be reported immediately. This can be serious and usually needs steroids and stopping the drug.

Monitoring, when to call, and simple tips

Before you start: get baseline tests — fasting glucose, A1c, liver tests, and a CBC. Your team will tell you how often to repeat them. A common plan is frequent glucose checks early on and regular liver and blood‑count tests while you’re on treatment.

Call your doctor right away for high fever, severe rash or blistering, sudden breathing trouble, fainting, persistent vomiting or diarrhea, or signs of very high blood sugar (extreme thirst, confusion, passing out). If you’re pregnant or planning to become pregnant, do not take alpelisib.

Quick tips: keep a glucose meter handy, carry a list of medications, use moisturizer and sunscreen, stay hydrated, and ask your team about steps they’ll take if a side effect appears. Small actions and early reporting help keep treatment on track.

If anything feels off, speak up. Your oncologist can adjust the dose, pause treatment, or prescribe medicines that make side effects easier to handle.