Skip to Content

Kisqali Femara Co-Pack Side Effects

Generic Name: letrozole / ribociclib

Note: This document contains side effect information about letrozole / ribociclib. Some of the dosage forms listed on this page may not apply to the brand name Kisqali Femara Co-Pack.

For the Consumer

Applies to letrozole / ribociclib: oral tablet

Along with its needed effects, letrozole/ribociclib may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking letrozole / ribociclib:

More Common

  • Black, tarry stools
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bloody or cloudy urine
  • chills
  • cough
  • decrease in height
  • difficult, burning, or painful urination
  • difficult or labored breathing
  • fever
  • frequent urge to urinate
  • lower back or side pain
  • pain in the back, ribs, arms, or legs
  • pale skin
  • sore throat
  • tightness in the chest
  • tingling of the hands or feet
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • unusual weight gain or loss

Some side effects of letrozole / ribociclib may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More Common

For Healthcare Professionals

Applies to letrozole / ribociclib: oral tablet


The most common adverse reactions and laboratory abnormalities (20% or more frequency) were decreased leukocyte count (93%), decreased neutrophil count (93%), neutropenia (75%), decreased hemoglobin count (57%), nausea (52%), decreased lymphocyte count (51%), increased ALT (46%), increased AST (44%), fatigue (37%), diarrhea (35%), alopecia (33%), leukopenia (33%), decreased platelet count (29%), vomiting (29%), constipation (25%), headache (22%), back pain (20%), and increased creatinine (20%).[Ref]


Very common (10% or more): Decreased leukocyte count (93%), decreased neutrophil count (93%), neutropenia (75%), decreased hemoglobin count (57%), decreased lymphocyte count (51%), leukopenia (33%), decreased platelet count (29%), anemia (18%), lymphopenia (11%)[Ref]


Very common (10% or more): Nausea (52%), diarrhea (35%), vomiting (29%), constipation (25%), stomatitis (12%), abdominal pain (11%)[Ref]


Very common (10% or more): Increased ALT (46%), increased AST (44%), abnormal liver function tests (18%)

Frequency not reported: Increased blood bilirubin[Ref]


Very common (10% or more): Fatigue (37%), pyrexia (13%), peripheral edema (12%)

Uncommon (0.1% to 1%): On-treatment death[Ref]


Very common (10% or more): Alopecia (33%), rash (17%), pruritus (14%)[Ref]

Nervous system

Very common (10% or more): Headache (22%)

Common (1% to 10%): Syncope[Ref]


Very common (10% or more): Back pain (20%)

Common (1% to 10%): Fractures

Uncommon (0.1% to 1%): Osteoporosis[Ref]


Very common (10% or more): Increased creatinine (20%)[Ref]


Very common (10% or more): Decreased appetite (19%), decreased phosphorus (13%), decreased potassium (11%)

Frequency not reported: Hypokalemia[Ref]


Very common (10% or more): Insomnia (12%)[Ref]


Very common (10% or more): Dyspnea (12%)[Ref]


Very common (10% or more): Urinary tract infection (11%)[Ref]


Common (1% to 10%): QT interval prolongation[Ref]


1. "Product Information. Kisqali Femara Co-Pack (letrozole-ribociclib)." Novartis Pharmaceuticals, East Hanover, NJ.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.