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Lomustine Side Effects

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

For the Consumer

Applies to lomustine: oral capsule

Along with their needed effects, medicines like lomustine 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.

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

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


In one study of 17 patients receiving an average of 12 weekly 30 mg/m2 dosages, 6 patients (35%) developed thrombocytopenia and 3 patients (18%) developed neutropenia.[Ref]

Hematologic side effects including myelosuppression have been reported. Delayed myelosuppression is the most frequent and serious toxicity associated with lomustine therapy. This effect most frequently occurs from 4 to 6 weeks after drug administration and is dose related. Thrombocytopenia occurs approximately 4 weeks after drug administration and persists for about 1 to 2 weeks. Leukopenia generally occurs approximately 5 to 6 weeks after drug administration and also lasts for about 1 to 2 weeks. In patients receiving dosages of 130 mg/m2, approximately 65% develop white blood counts below 5000 wbc/mm3, and 36% develop counts below 3,000 wbc/mm3. Thrombocytopenia is generally more severe than leukopenia. Both may be dose limiting.

Cumulative myelosuppression, manifested by more depressed indices or longer duration of suppression after repeated doses, have been reported. Acute leukemia and bone marrow dysplasias have been reported in patients following long term nitrourea therapy.

Anemia has been reported less frequently and is also cumulative.[Ref]


The onset of respiratory toxicity has been reported to occur 6 months or longer from the start of therapy. Cumulative doses are usually greater than 1100 mg/m2. The drug should be discontinued after a cumulative dose of 1400 mg.

There is one case report of a fatality due to pulmonary toxicity at a cumulative dose of 600 mg. Delayed onset pulmonary fibrosis occurring up to 15 years after treatment has been reported in patients who received nitrosoureas in childhood and early adolescence combined with cranial radiotherapy for intercranial tumors.[Ref]

Respiratory side effects including pulmonary infiltrates and/or fibrosis have been reported rarely.[Ref]


Prior administration of antiemetics is effective in decreasing and sometimes preventing nausea and vomiting. This side effect can also be reduced if the patient fasts prior to dosage administration. Due to rapid absorption, vomiting one to two hours after lomustine administration will not interfere with the effectiveness of lomustine.[Ref]

Gastrointestinal side effects including nausea and vomiting may occur 2 to 6 hours after an oral dose is ingested. This effect usually lasts less than 24 hours. Anorexia for 2 to 3 days duration has also been reported. Stomatitis has been reported infrequently. Mucositis has been reported rarely.[Ref]


Hepatic side effects including a reversible hepatic toxicity, manifested by increased transaminase, alkaline phosphatase and bilirubin levels, have been reported in a small percentage of patients.[Ref]


Renal side effects including progressive azotemia, decrease in kidney size, and renal failure have been reported in patients who have received large cumulative doses after prolonged therapy. Renal damage has also occasionally been reported in patients receiving lower total dosages.[Ref]

Four case reports of nephrotoxicity involved cumulative doses of 3320 mg, 2300 mg, 3360 mg and 3530 mg. In animal testing, lomustine caused fatal chronic interstitial nephritis in monkeys.[Ref]

Nervous system

The relationship of the nervous system side effects to lomustine therapy is unclear.[Ref]

Nervous system side effects including disorientation, lethargy, ataxia and dysarthria have been reported rarely.[Ref]


Dermatologic side effects including alopecia have been reported infrequently.[Ref]


1. "Product Information. CeeNU (lomustine)." Bristol-Myers Squibb, Princeton, NJ.

2. "Multum Information Services, Inc. Expert Review Panel"

3. Koller CA, Gorski CC, Benjamin RS, Legha SS, Papadopoulos NE, Plager C "A phase I trial of weekly lomustine in patients with advanced cancer." Cancer 73 (1994): 236-9

4. Dent RG "Fatal pulmonary toxic effects of lomustine." Thorax 37 (1982): 627-9

5. Weiss RB, Poster DS "THE RENAL TOXICITY OF CANCER CHEMOTHERAPEUTIC AGENTS." Cancer Treat Rev 9 (1982): 37-561982

6. Ellis ME, Weiss RB, Kuperminc M "Nephrotoxicity of lomustine. A case report and literature review." Cancer Chemother Pharmacol 15 (1985): 174-5

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.