Thalidomide is used in the treatment of multiple myeloma and lepra reaction.

Thalidomide modulates the activity of body's immune system and helps indirectly attacking the cancer cells. It also stops the growth of blood vessels in cancer.

Headache, Sleepiness, Nausea, Rash, Breathlessness, Weakness, Dizziness, Edema, Loss of appetite, Decreased white blood cell count, Decreased calcium level in blood, Weight gain, Fatigue, Muscle weakness, Fever, Anxiety, Blood clots , Dry skin, Weight loss, Confusion, Decreased white blood cell count (neutrophils), Neuropathy, Constipation, Tremor

• Use an effective method of contraception for 4 weeks before starting treatment, during treatment, and until 4 weeks after stopping treatment. 
• Before taking thalidomide inform your doctor if you have had a heart attack, have ever had a blood clotting related disorder, or if you smoke, have high blood pressure or high cholesterol levels, have existing slow heart rate (this may be symptoms of bradycardia), existing neuropathy i.e. tingling, abnormal co-ordination or pain in your hands or feet, sleepiness, a condition called Tumor Lysis Syndrome, severe infections. 
• Consult a doctor if you develop allergic reaction such as rash, itching, swelling, dizziness or trouble breathing during thalidomide therapy. 
• Avoid donating blood during thalidomide treatment and for 1 week after stopping treatment. 
• Do not drive or operate machinery as thalidomide may cause fatigue, dizziness, somnolence and blurred vision.
• Tell your doctor if you are or planning to become pregnant or are breastfeeding.