Yes. I was not told this specifically for Tysabri but I was told this generally for all MS meds.

It doesn't matter what the size of a person is with regard to MS meds. The MS meds treat the CNS system or the immune system, which is about the same regardless of size within the same species. They don't grow with increasing size. It would be different amounts for different species.

From the tysabri.com site:

http://www.tysabri.com/tysbProject/tysb.portal/_baseurl/twoColLayout/SCSRepository/en_US/tysb/home/index.xml

A bolus or a push is just running the meds faster than 1 hour by pushing it into the artery with a saline bag.

---------------------------------DOSAGE AND ADMINISTRATION ---------------------------------
300 mg infused intravenously over approximately one hour, every four weeks. Do not give as an intravenous push or bolus (2.1, 2.2).
TYSABRI solution must be administered within 8 hours of preparation (2.3).
Observe patients during the infusion and for one hour after the infusion is complete (2.4).
In CD, discontinue in patients that have not experienced therapeutic benefit by 12 weeks of induction therapy, and in patients that cannot discontinue chronic concomitant steroids within six months of starting therapy (2.2).
---------------------------------DOSAGE FORMS AND STRENGTH --------------------------------
Solution [300 mg per 15 mL vial] for dilution prior to infusion (3).
-----------------------------------------CONTRAINDICATIONS ---------------------------------------
Patients who have or have had PML (4).
Patients who have had a hypersensitivity reaction to TYSABRI (4).
---------------------------------WARNINGS AND PRECAUTIONS----------------------------------
Progressive Multifocal Leukoencephalopathy (PML): Has occurred in patients who received TYSABRI. Patients who have significantly compromised immune system function should not ordinarily be treated with TYSABRI. Obtain an MRI scan in MS patients prior to initiating TYSABRI. Monitor MS and CD patients and withhold TYSABRI at the first sign or symptom suggestive of PML (5.1).
Hypersensitivity reactions: Serious hypersensitivity reactions (e.g., anaphylaxis) have occurred. Permanently discontinue TYSABRI if such a reaction occurs (5.3).
Immunosuppression/Infections: TYSABRI may increase the risk for certain infections. Monitor patients for development of infections due to increased risk with use of TYSABRI (5.4).
Hepatotoxicity: Clinically significant liver injury has occurred. Discontinue TYSABRI in patients with jaundice or evidence of liver injury (5.5).
-----------------------------------------ADVERSE REACTIONS ----------------------------------------
The most common adverse reactions (incidence 10%) in MS were headache, fatigue, arthralgia, urinary tract infection, lower respiratory tract infection, gastroenteritis, vaginitis, depression, pain in extremity, abdominal discomfort, diarrhea NOS, and rash; and in CD were headache, upper respiratory tract infections, nausea, and fatigue (6.1)
To report SUSPECTED ADVERSE REACTIONS, contact Biogen Idec or Elan at 1-800-456-2255 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.