Ondansetron is a 5-HT3 receptor antagonist used to prevent and treat nausea and vomiting.

Applications:

• Prevents nausea and vomiting from chemotherapy, radiation, and surgery.

• Sometimes used for severe morning sickness in pregnancy.

Side Effects:

• Common: headache, constipation, dizziness.

• Serious (rare): QT prolongation, allergic reactions, serotonin syndrome (when combined with other serotonergic drugs).

Promethazine Hydrochloride is an antihistamine with antiemetic, sedative, and anticholinergic properties.

Applications:

• Treats nausea, vomiting, and motion sickness.

• Used as a sedative or for allergy symptoms.

• Sometimes used pre/post-surgery for nausea control.

Side Effects:

• Common: drowsiness, dry mouth, dizziness.

• Serious (rare): respiratory depression (especially in children), severe tissue damage if injected improperly.

Bisacodyl is a stimulant laxative used to treat constipation and prepare the bowel for medical procedures.

Applications:

• Relieves occasional constipation.

• Used for bowel cleansing before colonoscopy or surgery.

Side Effects:

• Common: abdominal cramps, diarrhea, nausea.

• Serious (rare): electrolyte imbalance, dehydration with prolonged use.