is tagamet constipation
1 Cimetidine (Tagamet, Tagamet HB). 2  Cimetidine (Tagamet) is the oldest H2 blocker. 3  It has few side effects; approximately 1% of people taking it will experience mild temporary diarrhea, dizziness, rash, or headache.alcium carbonate (Tums, Titralac, and Alka-2) is a potent and rapid acting antacid that can cause constipation. These antacids are actually sources of calcium. There have been rare cases of hypercalcemia (elevated levels of calcium in the blood) in people taking calcium carbonate for long periods of time.