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Gleostine Side Effects

Generic Name: lomustine

Note: This page contains information about the side effects of lomustine. Some of the dosage forms included on this document may not apply to the brand name Gleostine.

For the Consumer

Applies to lomustine: oral capsule

Along with their needed effects, medicines like lomustine (the active ingredient contained in Gleostine) can sometimes cause unwanted effects such as blood problems, loss of hair, and other side effects; these are described below. Also, because of the way these medicines act on the body, there is a chance that they might cause other unwanted effects that may not occur until months or years after the medicine is used. These delayed effects may include certain types of cancer, such as leukemia. Discuss these possible effects with your doctor.

In addition to its needed effects, some unwanted effects may be caused by lomustine. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking lomustine:

More common:
  • Bleeding gums
  • chest pain
  • shortness of breath
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Less common:
  • Awkwardness
  • black, tarry stools
  • blood in the urine or stools
  • confusion
  • cough or hoarseness
  • decrease in urination
  • fever or chills
  • lower back or side pain
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • slurred speech
  • swelling of the feet or lower legs
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Incidence not known:
  • Abdominal or stomach pain or tenderness
  • bone pain
  • change in frequency of urination or amount of urine
  • clay colored stools
  • dark urine
  • decreased appetite
  • dizziness
  • drowsiness
  • dry mouth
  • headache
  • increased blood pressure
  • increased thirst
  • itching
  • loss of appetite
  • nausea or vomiting
  • skin rash
  • weight gain
  • yellow eyes or skin

Minor Side Effects

Some of the side effects that can occur with lomustine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Darkening of the skin
  • diarrhea
Incidence not known:
  • Blurred vision
  • changes in patterns and rhythms of speech
  • confusion about identity, place, and time
  • decreased vision
  • eye pain
  • hair loss or thinning of the hair
  • shakiness and unsteady walk
  • swelling or inflammation of the mouth
  • trouble with speaking
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

For Healthcare Professionals

Applies to lomustine: oral capsule


Very common (10% or more): Decreased white blood counts (up to 65%), leukopenia
Frequency not reported: Myelosuppression/bone marrow suppression, thrombocytopenia, anemia, pancytopenia decreased hematocrit, bone marrow failure[Ref]


Very common (10% or more): Nausea and vomiting (45% to 100%)
Very rare (less than 0.01%): Diarrhea
Frequency not reported: Stomatitis, anorexia, loss of appetite[Ref]


Rare (less than 0.1%): Cholestatic jaundice
Frequency not reported: Elevations in transaminases, alkaline phosphatase, and bilirubin levels[Ref]


Frequency not reported: Progressive azotemia, decreased kidney size, renal failure, kidney damage, elevated BUN levels, renal atrophy, renal injury[Ref]


Rare (less than 0.1%): Pulmonary toxicity, interstitial pneumonia, lung fibrosis
Frequency not reported: Lung infiltration[Ref]


Frequency not reported: Acute leukemia, bone marrow dysplasia, myelodysplastic syndrome[Ref]

Nervous system

Uncommon (0.1% to 1%): Apathy, disorientation, confusion, stuttering
Frequency not reported: Lethargy, ataxia, dysarthria, abnormal coordination[Ref]


Frequency not reported: Optic atrophy, visual disturbances (e.g., blindness)[Ref]


Frequency not reported: Alopecia[Ref]


1. "Product Information. Gleostine (lomustine)." NextSource Biotechnology, LLC, Miami, FL.

Not all side effects for Gleostine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.