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Magnesium Family of Monographs

Type of Posting: Notice of Intent to Revise
Posting Date: 27–Aug–2021*    
Targeted Official Date: 1-Dec-2022; Revision Bulletin
Expert Committee: Small Molecules 3 

In accordance with the Rules and Procedures of the Council of Experts, this is to provide notice that the Small Molecules 3 Expert Committee intends to revise the following monographs:

  • Magnesium Carbonate 
  • Magnesium Hydroxide 
  • Magnesium Hydroxide Paste
  • Magnesium Oxide 
  • Magnesium Trisilicate 
  • Milk of Magnesia
  • Magnesia Tablets

Several comments were received detailing the difficulty with performing the new analytical method, in meeting the new assay specifications, and with performing a new Identification B for the magnesium monographs listed above.       

As an interim solution to avoid potential drug shortages, the Expert Committee proposes to revert the monographs to the previous versions that were official prior to June 1, 2021. USP encourages stakeholders to provide feedback on this proposed revision by Oct 1, 2021.

In the absence of significant adverse comments, it is anticipated that the proposed revision will be published as a Revision Bulletin (RB) on November 19, 2021 pursuant to the Rules and Procedures. The RB is anticipated to be official December 1, 2022, one year from the time of publication. USP allows early adoption of the RB as outlined in the USP General Notices 3.10. Applicability of Standards. Thus, once the RB is published, users will be able to early adopt the reverted monographs (versions official prior to June 1, 2021) or to continue to use the monographs with the new analytical method and specification (version official on June 1, 2021).

Additional information about that topic can be found in the Frequently Asked Questions for the Magnesium Family of monographs.

Should you have any questions or feedback, please contact Michael Chang, Principal Scientist (

*This Notice supersedes the previous notice on Magnesium Hydroxide and Magnesium Hydroxide Paste published on July 30, 2021  .