Letrozole / ribociclib Side Effects

Medically reviewed by Drugs.com. Last updated on Dec 5, 2023.

Applies to letrozole / ribociclib: oral tablet.

Serious side effects

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

Less common

• Chest pain
• confusion
• dark urine
• fainting
• general feeling of discomfort or illness
• irregular heartbeat
• loss of appetite
• mood or mental changes
• muscle cramps in the hands, arms, feet, legs, or face
• nausea
• numbness and tingling around the mouth, fingertips, or feet
• pain or tenderness in the upper stomach
• pale stools
• seizures
• stomach cramps
• thickening of bronchial secretions
• tremor
• vomiting
• yellow eyes or skin

Incidence not known

• Blistering, peeling, loosening of skin
• diarrhea
• joint or muscle pain
• rash or itching skin
• red irritated eyes
• red skin lesions, often with a purple center
• swollen glands

Other side effects

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

• Back pain
• constipation
• dry skin
• headache
• lack or loss of strength
• loss or thinning of the hair
• mouth or throat pain
• swelling or inflammation of the mouth
• trouble sleeping

Less common

• Belching
• dry eye
• heartburn
• increased tearing
• indigestion
• patchy loss of skin color

For Healthcare Professionals

Applies to letrozole / ribociclib: oral tablet.

General

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]

Hematologic

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]

Gastrointestinal

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

Hepatic

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

Frequency not reported: Increased blood bilirubin^[Ref]

Other

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

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

Dermatologic

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]

Musculoskeletal

Very common (10% or more): Arthralgia (33%), back pain (20%)

Common (1% to 10%): Fractures

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

Renal

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

Metabolic

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

Frequency not reported: Hypokalemia^[Ref]

Psychiatric

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

Respiratory

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

Genitourinary

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

Cardiovascular

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

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.

Medical Disclaimer