# Post-dose Observation
Keywords: TYSABRI, natalizumab, subcutaneous, intravenous, post-dose observation, hypersensitivity, injection reactions, infusion reactions, clinical judgement

> This page provides information about post-dose observation requirements for patients receiving TYSABRI (natalizumab) via subcutaneous (SC) or intravenous (IV) administration, including potential reductions or removal of observation time based on clinical judgement.

## Details
- [Potential for post-dose observation to be reduced or removed](#): Patients receiving TYSABRI SC or IV should be observed for hypersensitivity reactions during and after administration, with the possibility of reducing or removing observation time after specific doses if no reactions occur.
- [TYSABRI SC](#): After the first 6 doses of natalizumab (SC or IV), the observation time may be reduced or removed based on clinical judgement if no injection reactions are experienced.
- [TYSABRI IV](#): After the first 12 IV doses of TYSABRI, the observation time may be reduced or removed based on clinical judgement if no infusion reactions are experienced.
- [Dosing and post-dose observation examples](#): Examples are provided for TYSABRI-naïve SC and IV patients, as well as for patients switching from IV to SC, detailing when observation time may be reduced or removed.
- [Adverse event reporting](#): Adverse events should be reported to the relevant authorities in the UK and Ireland, with specific contact details and resources provided for healthcare professionals.