L22- GIT Drugs I (antacids) Flashcards
1
Q
Antacids:
- (1) definition
- (2) mechanism
A
1- weak bases (no Rx)
2- Antacid + HCl —> salt + H2O
2
Q
Antacid time of onset and duration of action
A
Onset- 5 mins
Duration 1/2-1 hr
3
Q
list the classic antacid formulations
A
AlOH, aluminum hydroxide
MgOH, magnesium hydroxide
CaCO3, calcium carbonate (Tums)
4
Q
Indicate the antacid associated with the following:
- (1) osmotic diarrhea
- (2) constipation
- (3) CO2 causes belching leading to (4)
A
1- MgOH
2- AlOH
Note- MgOH, AlOH can be combined to net no changes in BMs
3- calcium carbonate
4- metabolic acidosis // milk alkali syndrome
5
Q
discuss the main adverse effect of antacids
A
Dec absorption of co-administered drugs:
- includes tetracylcines, fluoroquinolones, itraconazole, iron
- result of binding / chelation to many drugs
- inc gastric pH –> alters weakly charged drugs