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.
Unlike most other movement disorders, children can sometimes consciously suppress tremors. Myoclonus Myoclonus is a movement disorder involving very quick, sudden, involuntary muscle jerks that the child cannot suppress.