Levamisole (Oral)


When prescribed in isolation, Levamisole is most-commonly used to treat skin conditions and parasitic infections. However, Levamisole can improve the effects of antineoplastic agents and has, therefore, been used in the treatment of colon cancer.

Patients with colon cancer are often treated with surgery but may require further treatment if cancer cells remain. Whilst Fluorouracil is often used as a form of chemotherapy for patients with cancer of the colon, it is more effective when used in conjunction with Levamisole.

As Fluorouracil prevents cell replication by acting as a thymidylate synthesis inhibitor, it affects healthy cells, as well as cancer cells. Due to this, Fluorouracil can suppress the patient's immune system and leave them vulnerable to infections and other illnesses. When supplemented with Levamisole, however, the effects of Fluorouracil on the immune system are minimized. Whilst the drug is still able to inhibit cell replication and, therefore, the spread of cancer, the patient's immune system is not suppressed to such a great degree. As a result, patients can tolerate treatment more easily and are less likely to succumb to infections during and following treatment.

In addition to this, Levamisole increases the production of specific immune system proteins; class I human leukocyte antigens. Responsible for regulating the immune system, these antigens can have a positive effect when they are produced in higher numbers. Levamisole can, therefore, improve the functioning of the patient's immune system, whilst reducing the damage and toxicity caused by other medications, such as Fluorouracil.

Conditions Treated

  • Cancer of the colon

Type Of Medicine

  • Synthetic Imidazothiaziole derivative
  • Anthelmintic agent
  • Anti-parasitic agent
  • Immunotherapeutic agent

Side Effects

When patients first start Levamisole, they may exhibit some side effects. Often, these will diminish over time and will not require additional treatment. For example, the following side effects may occur when patients first start using this medication:

  • Anxiety or nervousness
  • Metallic taste
  • Dizziness
  • Nausea
  • Headache
  • Diarrhea
  • Vomiting
  • Mental depression
  • Pain in muscles or joints
  • Nightmares
  • Unusual sleepiness or tiredness
  • Trouble sleeping
  • Skin itching or rash

Providing the above side effects are fairly short-lived and are not severe, patients may not require medical intervention. However, if these side effects persist or are troublesome for the patient, medical help should be sought.

Patients should also notify their physician if they experience any of the following adverse effects when taking Levamisole:

  • Blurred vision
  • Sores on the lips or in the mouth
  • Confusion
  • Uncontrolled movements of the legs or arms
  • Rapid or worm-like movements of tongue
  • Convulsions (seizures)
  • Trouble in walking
  • Puffing of the cheeks
  • Lip puffing or smacking
  • Pain, tingling or numbness in hands, feet or face
  • Shaking or trembling
  • Paranoia (feelings of persecution)

Furthermore, patients should obtain immediate medical help if they exhibit any of the following side effects during or following treatment with Levamisole:

  • Fever or chills
  • Tarry, black stools
  • Blood in the stools or urine
  • Unusual feeling of weakness or discomfort
  • Hoarseness or cough
  • Unusual bruising or bleeding
  • Pain in the lower back or side
  • Difficult or painful urination
  • Red pinpoint spots on skin

If patients develop any other side effects when taking Levamisole, they should also seek medical help.


As Levamisole is a fairly new form of treatment for colon cancer, standardized doses have yet to be established. In most cases, the patient's dose of Levamisole will depend on how often they are treated with Fluorouracil, as well as their clinical presentation, medical history, age and weight.

When taking Levamisole, patients should follow their doctor's instructions. It is important that patients only take the dose which has been prescribed to them and that they do not take more medication than has been advised and that they do not take Levamisole more often than has been prescribed. Doing so could result in serious health problems occurring.

If patients vomit or have severe diarrhea after taking a dose of Levamisole, they will need to seek medical advice. A doctor will be able to confirm whether the patient should take another dose of Levamisole or whether they should wait until their next dose is due to take more medication.

Similarly, if patients forget to take a dose of Levamisole, they should contact their physician or pharmacist for advice. Patients should not simply attempt to take an extra or double dose of Levamisole, even if an earlier dose has been missed.

If patients are unsure how or when to take Levamisole, they should contact their physician or pharmacist for further advice.

Potential Drug Interactions

If Levamisole is taken in conjunction with some other medications, it may increase the patient's risk of developing side effects. For example, taking Levamisole alongside the following medicines may cause increased side effects to occur:

  • Capecitabine
  • Tegafur
  • Doxifluridine
  • Warfarin
  • Fluorouracil

If patients are advised to take Levamisole alongside any of the above medications, their dose may be modified to reduce the risk of side effects occurring. Alternatively, patients may be advised to take their medication at a specific time as this could help to prevent them from suffering from adverse effects. If necessary, patients may be given additional medication to treat any side effects which occur as a result of their treatment with Levamisole and other medications.

Before patients start taking Levamisole, they should tell their physician if they are using any other medications or substances. This includes prescription medications, over-the-counter medicines, vitamins and/or supplements. Once patients have started taking Levamisole, they will need to obtain medical advice before they start using any new medicines, vitamins and/or supplements.


If patients have any existing medical problems or a history of certain conditions, they should notify their physician before they begin taking Levamisole. There are some conditions which may affect the use of Levamisole so it is vital that patient's disclose all relevant information to their physician before treatment with Levamisole is commenced. For example, patients may not be treated with Levamisole if they are suffering from an infection. Physicians may treat the patient's infection first, before starting treatment with Levamisole.

By disclosing their medical history and current health problems, patients can ensure that they receive an appropriate dose of Levamisole and that treatment with this medication is suitable for them.

To date, the effects of Levamisole in treating colon cancer have only been studied in adult patients. Due to this, pediatric patients should not be treated with Levamisole, even if the medication is used alongside other anti-cancer medications.

When patients are taking Levamisole, they will need to have regular check-ups and consultations with their physician. In addition to this, regular blood tests may be carried out in order to determine what effect the medication is having. These tests help physicians to modify the patient's dose when necessary and to confirm that patients are not suffering from any unwanted effects.

If Levamisole is taken by patients who are pregnant, it may cause harm to the unborn fetus. Due to this, Levamisole should not be used by pregnant patients unless there is no safer alternative available and the benefits greatly outweigh the risks.

Whilst receiving treatment with Levamisole and other antineoplastic agents, patients may be advised to use a reliable form of birth control. Similarly, patients may be instructed to continue using effective birth control following their final dose of Levamisole as the drug may remain in their system.

If patients become pregnant during or following treatment with Levamisole, they should notify their physician straight away.

Although some medicines can be excreted in breast milk, it is not known if Levamisole is present in breast milk produced by nursing mothers. Furthermore, it is not known what risk Levamisole would present to an infant if it was transferred to them via breastfeeding. Due to this, patients are usually advised not to breastfeed whilst taking this medication or for as long as the drug remains in their system.

Before patients start taking Levamisole, they should inform their doctor if they have any existing allergies. In rare cases, patients may exhibit an allergic reaction when taking Levamisole and, if so, they will require emergency medical treatment. The symptoms of an allergic reaction may include:

  • Difficulty swallowing
  • Difficulty breathing
  • Hives
  • Wheezing
  • Itching
  • Shortness of breath
  • Hoarseness
  • Swelling of the face, tongue, lips, throat, mouth or hands
  • Rash on the skin


When patients are required to keep Levamisole at home, they should follow the manufacturer's storage instructions and the medication guidelines. In most cases, however, Levamisole can be kept at room temperature but should be stored in a closed container. If Levamisole tablets are supplied in a blister pack, patients should leave the medication in its original packaging and only remove a tablet when they are ready to take it. In addition to this, Levamisole should be protected from heat, moisture and light.

Patients must ensure that medications, such as Levamisole, are kept in a safe place and that children and/or pets cannot gain access to them.

If patients are advised to stop using Levamisole or if the medication reaches its expiration date, patients should dispose of the medication carefully. Levamisole should not be thrown out with regular household waste as it may pose a risk to other people. Instead, patients should contact their physician's office or pharmacist and make use of a designated medicine disposal service.


Although Levamisole is a fairly new form of treatment for colon cancer, it has been shown to increase the efficacy of cancer treatments. When used in conjunction with other antineoplastic medicines, Levamisole can limit the damage caused to the patient's immune system and increase the number of class I human leukocyte antigens in the patient's system. As a result, Levamisole helps the patient's immune system to function more effectively and can improve treatment outcomes.

Whilst many anti-cancer medications are delivered via intravenous injection, Levamisole can be taken orally. For patients, this is often a more convenient way to take their medication and means that Levamisole can easily be used to supplement other treatments. By combining Levamisole therapy with other anti-cancer medicines, physicians can improve the patient's prognosis and significantly increase survival rates of cancers of the colon.