Essentially sodium-free effervescent solid pharmaceutical compositions

An effervescent solid pharmaceutical composition comprising:

• an active pharmaceutical ingredient, wherein the active pharmaceutical ingredient is lacosamide;
• one or more of a pharmaceutically acceptable alkaline earth metal carbonate or hydrocarbonate thereof in an amount in a range from 1 to 31% by weight of the composition, wherein the one or more of the pharmaceutically acceptable alkaline earth metal carbonate or hydrocarbonate thereof comprise calcium carbonate or magnesium carbonate;
• one or more of a pharmaceutically acceptable acid, a salt thereof, or a mixture thereof, in an amount in a range from 2 to 62% by weight of the composition, wherein the one or more of the pharmaceutically acceptable acid, the salt thereof, or the mixture thereof is at least one material selected from the group consisting of citric acid, malic acid, glycine hydrochloride, fumaric acid, tartaric acid, and glutamic acid;
• and
• one or more of a pharmaceutically acceptable excipient or a pharmaceutically acceptable carrier,
• wherein a total content of an ion sodium in the effervescent solid pharmaceutical composition is equal to or lower than 1 mmol,
• wherein a molar ratio between the one or more of the pharmaceutically acceptable acid, the salt thereof, or the mixture thereof, and the one or more of the pharmaceutically acceptable alkaline earth metal carbonate or hydrocarbonate thereof, is in a range from 1.05:1 to 1.07:1, and
• wherein the effervescent solid pharmaceutical composition is provided in a tablet formulation.