Well think about it.... Pediatrics for example are most likely afraid or intolerant of different routes for exanple, not tolerating intravenous and being scared of intramuscular or other injection type things. They would probably be more tolerant of something not considered invasive for example subcutaneous or ingestion. A child body size and metabolism would also be quite fast at receiving the effects of such. Geriatrics do not feel as much pain and because of the slowed down metabolism probably would require routes that are much faster and would be more tolerant of more invasive routes. Pregnant women would probably prefer something slow acting or would not be metabolized at such a rate that it be dangerous toward the child.
