Disadvantages of injections include potential pain or discomfort for the patient and the requirement of trained staff using aseptic techniques for administration.  However, in some cases, patients are taught to self-inject, such as SC injection of insulin in patients with insulin-dependent diabetes mellitus . As the drug is delivered to the site of action extremely rapidly with IV injection, there is a risk of overdose if the dose has been calculated incorrectly, and there is an increased risk of side effects if the drug is administered too rapidly. 
Researchers also looked at how much patients were bothered by a combination of MS symptoms and AEs before, during, and after treatment. What they found was that the combined effect of symptoms and side effects was not substantially different between baseline and one week after treatment. This suggests that one week after treatment, the benefit gained from a decrease in MS symptoms was neutralized somewhat by the increased burden of adverse events related to treatment. Interestingly, the combined burden was the lowest on Day Two of IVMP treatment.