Thalomid (Thalidomide) – Oral


The Food and Drug Administration (FDA) has issued a boxed warning for Thalomid. Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning states:

Thalomid must not be used in people who are pregnant. People must also avoid becoming pregnant while taking this medication. Even a single dose of Thalomid has caused severe (often fatal) birth defects when used during pregnancy.

Only those who have signed an informed consent and agree to the requirements of the Risk Evaluation and Mitigation Strategy (REMS) program may obtain and use Thalomid.

When used to treat multiple myeloma (MM), Thalomid can increase the risk of serious blood clots in the legs or lungs, as well as heart attacks and strokes.

What Is Thalomid?

Thalomid (thalidomide) is an orally administered prescription medication classified as an immunomodulatory agent that is used alongside the anti-inflammatory steroid dexamethasone to treat multiple myeloma (MM).

It is also used by itself to treat moderate to severe erythema nodosum leprosum (ENL). Thalomid is approved for people 12 and older.

As an immunomodulatory agent, thalidomide, the active ingredient in Thalomid, belongs to a group of drugs that target the pathways that treat MM.

Immunomodulatory agents can stimulate or suppress the immune system, depending on the demands of an individual's diagnosis.

What's more, an immunomodulatory agent may affect the immune system and help the body fight infection, cancer, or similarly dangerous conditions.

Thalomid can alter the way the immune system fights off cancer cells. It also prevents the cancer cells from making blood vessels for themselves to continue to grow.

While no generic version exists, Thalomid is available in the form of oral capsules to be taken by mouth.

Drug Facts

Generic Name: Thalidomide
Brand Name: Thalomid
Drug Availability: Prescription
Administration Route: Oral
Therapeutic Classification: Leprostatic
Available Generically: No
Controlled Substance: N/A
Active Ingredient: Thalidomide
Dosage Form(s): Capsule

What Is Thalomid Used For?

Thalomid has been approved by the FDA to treat MM.

MM is a cancer of the plasma cells that are found within blood and bone marrow. When used to treat MM, Thalomid is often prescribed along with a steroid called dexamethasone.

Dexamethasone, specifically categorized as a corticosteroid (a potent drug that can improve symptoms associated with autoimmune or inflammatory diseases), is commonly prescribed to lessen the effects associated with croup, arthritis, and asthma. Moreover, it is sometimes prescribed for those diagnosed with COVID-19.

MM is a relatively uncommon form of cancer. In the United States, the risk of getting it is 1 in 132 (0.76%).

It was estimated that 34,470 new U.S. cases would be diagnosed (19,100 for males vs. 15,370 for females) in 2022.

In addition to treating MM, Thalomid is also used for a skin condition called erythema nodosum leprosum.

ENL is recognized by painful red bumps or nodules appearing on the skin due to leprosy (a chronic infectious disease caused by Mycobacterium leprae). This diagnosis, categorized as a vasculitic type II reaction, is a deadly condition that can be fatal if not treated immediately. ENL can be recurrent and/or chronic.

How to Take Thalomid

Thalomid should be taken at bedtime, and around the same time every day. It should also be taken at least one hour after eating the last meal of the day and should be taken with water. The pills should not be crushed or broken, and should only be taken whole.

General dosing guidelines are as follows:

For MM: 200 milligrams orally once daily; the recommended dose of dexamethasone is 40 milligrams a day on days one through four, nine through 12, and 17–20 of each 28-day treatment cycle

For ENL: 100 to 300 milligrams a day for an episode of cutaneous ENL; up to 400 milligrams per day for severe cutaneous ENL

Keep the capsules in their packaging until you are ready to consume them. Do not open the capsules or touch them more than necessary.


Thalomid should be kept in its original packaging. Do not put it in a pill box or other container. Thalomid needs to be kept at room temperature. The pills should not be exposed to light.

It is very important that Thalomid is only handled by the person it's prescribed for. Wash hands thoroughlyafter handling it. 

If a caregiver needs to give the medication, they should wear gloves and wash their hands after removing the gloves.

Thalomid should be stored in a place where it cannot be reached by children or pets.

Off-Label Uses

In addition to MM and ENL, Thalidomide has been prescribed off-label to treat other conditions.

These off-label uses, which are for conditions not approved to be treated by the medication but that may be helped by it, include:

How Long Does Thalomid Take to Work?

Absorption of Thalomid is slow after oral administration. Specifically, its peak presence in the bloodstream has been measured two to five hours after administration.

What Are the Side Effects of Thalomid?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects.

If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at or 800-FDA-1088.

Common Side Effects

As with most medications, there are side effects that may be commonly experienced.

The most common side effects from Thalomid use are:

Severe Side Effects

The FDA has issued a boxed warning for Thalomid. Boxed warnings are the agency’s strongest warnings for serious and potentially life-threatening risks.

The boxed warning for Thalomid cautions users against taking the drug while pregnant and to avoid becoming pregnant due to the risk of serious and often fatal birth defects. It also warns that the drug can cause serious blood clots and a risk of heart attack and stroke.

Only those who have signed an informed consent and agree to the requirements of the Risk Evaluation and Mitigation Strategy (REMS) program may obtain and use Thalomid.

When used to treat MM, Thalomid can increase the risk of serious blood clots in the legs or lungs, as well as heart attacks and strokes.

If you think your symptoms are life-threatening or if you’re having a medical emergency, call 911. Serious side effects can include the following:

  • Urticaria (hives)
  • Peeling or blistering to the skin
  • Seizures (sudden, uncontrolled electrical activity in the brain)
  • Dysphagia (difficulty swallowing)
  • Symptoms of fever
  • Bradycardia (heartbeat slower than 60 beats per minute)

Long-Term Side Effects

If any side effect is uncontrolled or becomes severe over time, that side effect could last into the future, even if Thalomid has been subsequently discontinued. 

Report Side Effects

Thalomid may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Thalomid Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For erythema nodosum leprosum:
      • Adults and children 12 years of age and older—At first, 100 to 300 milligrams (mg) once a day. Your doctor may adjust your dose as needed.
      • Children younger than 12 years of age—Use and dose must be determined by your doctor.
    • For multiple myeloma:
      • Adults and children 12 years of age and older—200 milligrams (mg) once a day together with dexamethasone. The dose is repeated every 28 days.
      • Children younger than 12 years of age—Use and dose must be determined by your doctor.


Potential users should be aware of the following before beginning Thalomid:

Allergies: Do not take Thalomid if you are allergic to thalidomide or any of the ingredients in the medication. Moreover, avoid using it if you have experienced past allergic reactions from using other immunomodulatory agents.

Pregnancy: Thalomid can cause severe birth defects or embryo-fetal death. It should never be used by people who are pregnant or who could become pregnant. Even a single dose taken by a pregnant person during pregnancy can cause severe birth defects.

Breastfeeding: Due to limited research regarding the presence of Thalomid in human breast milk and the results of animal studies showing the presence of thalidomide in milk, it is advised to not breastfeed during treatment.

Children: The safety and effectiveness of pediatric individuals below the age of 12 have not been established. Therefore, consult with your healthcare provider to find alternative treatments.

Adults 65 and over: In one clinical trial, people 65 and older treated with Thalomid alongside dexamethasone experienced more occurrences of atrial fibrillation (irregular heartbeat), constipation, fatigue, nausea, hypokalemia (low potassium), hyperglycemia (high blood sugar), pulmonary embolism (blood clot of the lungs), and feelings of weakness versus those younger than 65. Therefore, speak with your healthcare provider if you believe your age will impact your tolerance of Thalomid and/or dexamethasone.

People with kidney impairment: Kidney issues are not expected to be a factor in tolerance as only a small percentage of a standard dose is expelled in the urine.

Missed Dose

If a dose is missed, it should be taken as soon as remembered, as long as it is within 12 hours of the missed dose. Any dose missed after 12 hours should be skipped.

Overall, never double up to account for a missed dose.

Overdose: What Happens If I Take Too Much Thalomid?

Studies are limited regarding Thalomid and overdose. However, if you feel that a dangerous amount has been consumed by yourself or a another person, notify your healthcare provider immediately.

What Happens If I Overdose on Thalomid?

If you think you or someone else may have overdosed on Thalomid, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Thalomid, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress closely at regular visits to see if the medicine is working properly and to allow for a change in the dose. Blood tests may be needed to check for unwanted effects.

Women should take the necessary precautions to avoid pregnancy while taking thalidomide. Begin 2 forms of effective birth control together 4 weeks before starting treatment, during treatment, even if the dose is stopped for a short time, and for at least 4 weeks after your last dose. Talk to your doctor about the most effective forms of birth control for you and your partner. Call your doctor right away if you think you are pregnant.

Women who can get pregnant must have a negative pregnancy test before starting treatment with this medicine. Pregnancy tests may be done weekly for the first month during treatment, and then every 2 to 4 weeks.

Men who are sexually active must protect their female partner from getting pregnant. Thalidomide will appear in the semen of male patients. If you are sexually active, you must use a latex or synthetic condom every time you have sex with a woman who could get pregnant. If you have had a vasectomy, you still have to use a latex condom during sex. You must use a condom during treatment, even if the dose is stopped for a short time, and for at least 4 weeks after your last dose. Call your doctor right away if you think your sexual partner may be pregnant.

Do not donate blood or sperm while you are taking this medicine and for at least 4 weeks after your last dose.

You must not share this medicine with anyone, even someone who has similar symptoms.

This medicine may increase your risk of having blood clots, a heart attack, or stroke. Check with your doctor right away if you have shortness of breath, chest pain, or leg pain or swelling. These could be symptoms of blood clots. Symptoms of stroke include confusion, difficulty with speaking, double vision, inability to move the arms, legs, or facial muscles, or slow speech.

Do not receive pembrolizumab together with thalidomide and dexamethasone if you have multiple myeloma.

This medicine may make you dizzy, drowsy, or lightheaded. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. If you feel lightheaded, getting up slowing after sitting or lying down may help.

Thalidomide can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

  • If you can, avoid people with infections. Check with your doctor right away if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
  • Check with your doctor right away if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
  • Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
  • Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
  • Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
  • Avoid contact sports or other situations where bruising or injury could occur.

This medicine may cause nerve damage. Check with your doctor right away if you have tingling, burning, numbness, or pain in your hands or feet. These could be symptoms of a nerve condition called peripheral neuropathy.

Check with your doctor right away if you have a fever, chills, cough, sore throat, swollen, painful, or tender lymph glands in the neck, armpit, or groin, or yellow skin or eyes while using this medicine. These could be symptoms of a serious condition called drug reaction with eosinophilia and systemic symptoms (DRESS).

This medicine may cause serious allergic reactions, including anaphylaxis, angioedema, or certain skin conditions, which can be life-threatening and require immediate medical attention. Call your doctor right away if you have a rash, itching, blistering, peeling, or loosening of the skin, fever or chills, trouble breathing or swallowing, or any swelling of your hands, face, mouth, or throat while you are using this medicine.

Thalidomide may cause a serious type of reaction called tumor lysis syndrome in patients with multiple myeloma. Call your doctor right away if you have less urine than normal, joint pain, stiffness, or swelling, lower back, side, or stomach pain, a rapid weight gain, swelling of the feet or lower legs, or unusual tiredness or weakness.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that may make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicines for hay fever, allergies, or colds, sedatives, tranquilizers, or sleeping medicine, prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Check with your doctor before taking any of these medicines while you are using thalidomide.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

What Are Reasons I Shouldn’t Take Thalomid?

The following are preexisting conditions that should be weighed with your healthcare provider before starting Thalomid, due to the potential for negative reactions:

Allergies: Thalomid is discouraged in people with a history of drug-related hypersensitivity to any component of the medication. Hypersensitivity reactions, including angioedema and anaphylactic reactions, have been reported with Thalomid.

Pregnancy/breastfeeding: Consuming Thalomid while pregnant has been found to cause severe birth defects, and special precautions must be followed if pregnancy is a possibility. Moreover, avoid the use of Thalomid when breastfeeding, as there is limited information available to rule out its presence in breast milk.

Due to the potential for birth defects, a special program, called Risk Evaluation and Mitigation Strategy (REMS), must be followed in order for the medication to be delivered.

Tolerance: A dose adjustment of Thalomid may be required if any side effect becomes severe, especially if the side effect is peripheral neuropathy (pain as a result of nerve damage, typically in the feet and hands), constipation, or drowsiness.

Seizure disorder, seizures: Seizures have been reported in people who received Thalomid; although it should be noted that most of these people had disorders that predisposed them to epileptic tendencies originally. However, it has not been proven that Thalomid has any seizure-inducing qualities. Nonetheless, inform your healthcare provider if you have a seizure disorder or possess risk factors for developing seizures.

What Other Medications Interact With Thalomid?

There are many other medications that should be avoided when taking Thalomid, as they can potentially increase side effects or cause potentially mild to severe negative reactions.

Medications generally discouraged when taking Thalomid include:

In addition, drinking alcohol when on Thalomid can lead to an increased risk of peripheral neuropathy and drowsiness.

This is not a complete list of drug interactions, and others may occur.

Before starting Thalomid, tell your healthcare provider about all your prescription and over-the-counter (OTC) medications, vitamins, and herbal supplements.

What Medications Are Similar?

Two other medications similar to Thalomid and in the same medication class are Revlimid (lenalidomide) and Pomalyst (pomalidomide).

Specifically, Revlimid is also used to treat MM and works very similarly to Thalomid, while many of the side effects are similar. However, the risk of developing blood clots is lower with Revlimid use vs. Thalomid.

Pomalyst is also used to treat MM and is less likely to cause severe peripheral neuropathy vs. Thalomid. 

It should be noted that these two medications are not to be taken along with Thalomid. Your cancer-fighting or ENL regimen will be determined by your healthcare provider.

Frequently Asked Questions

  • What is Thalomid used for?

    Thalomid is an orally prescribed medication used in combination with dexamethasone to treat MM and moderate to severe ENL.

  • How does Thalomid work?

    Thalomid works by instructing the immune system to fight off the abnormal cancer cells and keeps cancer cells from being able to make blood vessels for themselves.

  • What are the side effects of Thalomid?

    Side effects of Thalomid can include:

    • Peripheral neuropathy
    • Blood clots
    • Nausea
    • Lethargy
    • Dry mouth 
    • Loss of appetite
    • Dry skin 
    • swelling

How Can I Stay Healthy While Taking Thalomid?

The warnings and side effects of Thalomid may sound intimidating, but it can be a very effective medication in treating MM or ENL.

It's imperative to follow the instructions provided by your healthcare team regarding taking this drug, and always ask any questions if you have them. 

If you develop any side effects from Thalomid, the sooner you act to address them, the sooner you will feel better. 

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bristol Myers Squibb. Thalomid (thalidomide) prescribing information.

  2. National Cancer Institute. Nonspecific immunomodulating agent.

  3. American Cancer Society. Immunomodulators and their side effects.

  4. MedlinePlus. Thalidomide.

  5. American Cancer Society. What Is multiple myeloma?

  6. MedlinePlus. Dexamethasone.

  7. American Cancer Society. Key statistics about multiple myeloma.

  8. ScienceDirect. Erythema nodosum leprosum.

  9. Prescribers' Digital Reference. Thalomid - drug summary.

  10. Bristol Myers Squibb. Revlimid (lenalidomide) prescribing information.

  11. Bristol Myers Squibb. Pomalyst (pomalidomide) prescribing information.

  12. American Cancer Society. Drug therapy for multiple myeloma.

  13. American Cancer Society. Managing cancer-related side effects.

By Julie Scott, MSN, ANP-BC, AOCNP
Julie is an Adult Nurse Practitioner with oncology certification and a healthcare freelance writer with an interest in educating patients and the healthcare community.