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.
Contractions are called positive myoclonus; relaxations are called negative myoclonus. When falling asleep, it is common for people to experience a type of myoclonic jerk known as a hypnic jerk. Hiccups are also a kind of myoclonic jerk specifically affecting the diaphragm. Myoclonus is a symptom of a disease in which a muscle or group of muscles suddenly starts twitching or jerking. Some common examples of myoclonus are: 1  Hiccups. 2  a sudden violent jerking or twitching motion when one is startled; or, 3  the twitching of an arm or leg as you begin to fall asleep.