Final answer:
A large dose of medicine in a liquid form that is ingested orally is known as a drench. This route is useful for home administration of medication for systemic infections, and intravenous administration is used for fluids in dehydrated patients.
Step-by-step explanation:
A large dose of medicine in a liquid form that is ingested or administered by mouth is called a drench. The oral route is considered appropriate and convenient for home administration of an antimicrobial to treat a systemic infection. When a patient is dehydrated and needs to receive fluids intravenously, this is done through an intravenous administration, which ensures prompt fluid replenishment. It's also notable that intravenous administration of drugs generally leads to substantially higher plasma levels compared to oral or intramuscular administration. For medication that cannot be absorbed easily in the gastrointestinal tract or in cases where a patient cannot take oral medication, a parenteral route is preferred, usually within health-care settings.