Alka-Seltzer effervescent tablets contain aspirin, sodium hydrogen carbonate and additional ingredients that create a fizzing solution when combined with water to relieve headache pain, menstrual cramps, muscle aches and flu symptoms, according to its manufacturer Bayer Corporation. Alka-Seltzer is a combination of analgesic medications and antacid medications, explains Drugs.com.
The analgesics in Alka-Seltzer work to hinder the substances in the body that trigger inflammation, while the antacids in Alka-Seltzer work to balance out stomach acids and minimize discomfort. Individuals with bleeding conditions such as low blood platelets or hemophilia, as well as those who take anti-coagulant medications, should not take Alka-Seltzer. Children and teenagers with the chicken pox or flu viruses should also refrain from using the medication. Individuals who consume more than three alcoholic drinks per day and women who are pregnant or breast-feeding should consult with a physician prior to taking the medication, recommends Drugs.com. Medications such as ibuprofen may lower the effectiveness of Alka-Seltzer.
Common side effects of Alka-Seltzer include nausea, heartburn, stomach irritation and the urge to vomit, according to WebMD. Less common side effects include gas and abdominal swelling. Rare, but severe side effects include anemia, stomach bleeding, hives, skin blisters, appetite loss and wheezing.