81,75% of the mass of sodium GHB is the hydroxybutyrate, so a typical 2.5g dose of NaGHB will contain ~450mg sodium. This is comparable to slightly less than a gram of table salt.
If you drink plenty of water alongside, you shouldn't get hypernatremia unless you dose with extreme regularity. Consumption of GBL, free-acid GHB, 1,4BDO et cetera pose no risk of sodium intoxication.