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.
Myoclonus refers to a quick, involuntary muscle jerk. Hiccups are a form of myoclonus, as are the sudden jerks, or sleep starts, you may feel just before falling asleep. These forms of myoclonus occur in healthy people and rarely present a problem.