- (*)Because of the increased risk of venous thromboembolism in patients with multiple myeloma taking Lenalidomide and Dexamethasone, combined oral contraceptive pills are not recommended. If a patient is currently using combined oral contraception she should switch to one of the effective method listed above. The risk of venous thromboembolism continues for 4 to 6 weeks after discontinuing combined oral contraception. The efficacy of contraceptive steroids may be reduced during co-treatment with Dexamethasone.