Possible side effects of Alka-Seltzer effervescent tablets: All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome: Heartburn; nausea; upset stomach.
A myoclonic jerk is the brief, involuntary twitching of a muscle or group of muscles. It may be caused either by a sudden muscle contraction, or a sudden lapse of contraction.
Fasciculation, a small, local, involuntary muscle contraction. Myoclonic twitch, a jerk usually caused by sudden muscle contractions. Myokymia, a continuous, involuntary muscle twitch that affects the muscles of the face. Spasm, a sudden, involuntary contraction. Tic, an involuntary, repetitive, nonrhythmic action.