How does a physician use factors to determine the appropriate dose and route of administration?

A physician must take into account the patient's weight in order to determine the dose of a medication. For certain medications, they must also take into account the desired effects. For instance, when treating hypertension, depending on the severity of the patient's high blood pressure the dose of the medication may be increased. The route of administration is determined by how quickly the physician wants the medication to take effect. For more immediate effects, a physician may choose to have the medication administered through an IV or an injection as opposed to having the patient take the medication orally.