The Department of Health and Social Care has extended a serious shortage protocol for Levothyroxine 12.5mcg tablets.
The extension sees the SSP for the drug end on March 12 having been due to expire on March 5.
The PSNC said pharmacists must use "the latest version of an SSP before considering the supply of an alternative product."
"Expiry dates of an SSP may be brought forward or extended and the content may be amended at any time during the life of an SSP," the negotiator said.
Other current SSPs include Fluoxetine 10mg and 40mg tablets (March 31), Fluoxetine 30mg capsules (March 12) and Salazopyrin EN-Tabs 500mg (March 8).