Why can't I lie down for 30 minutes after taking Klor-Con 20mg, a Potassium supplement.

Klor Con 20 is a Potassium supplement.
Nausea, vomiting, gas, abdominal pain/discomfort, and diarrhea are common side-effects. The following advice is to prevent / reduce stomach upset
"Take each dose with a meal and a full glass of water liquid and do not lie down for 30 minutes after taking this medication. Do not take this medication on an empty stomach. Dividing your dose so that you can take smaller doses (2 to 4 times a day) may also reduce stomach upset. "