次の英文の和訳をお願いしたいです。
For a pharmaceutical agent to be effective in carrying out its selective action, the drug must be administered in an appopriate manner. Each route of drug administration has specific purposes, advantages, and disadvantages.
With this method, drugs formulated in liquid or solid form are absoebed into the body from the gastrointestinal tract(GIT). This is the most commonly used route. Oral drugs are convenient --- portable, oainless, easy to take. Also, administration can be carried out by the patient him or heself. However, the onset of the drug's effect is relatively slow.
In this case, the drug, usually in tablet form, is placed under the tongue. This produces a very fast onset of drug action because of the good blood supply to the area, but the duration of the drug's effect is usually short.
This method can be used for patients who are unable to take drugs orally, or with younger children, elderly, or mentally disturbed patients. This route is usuful when a drug is known to cause GIT irritation. However, absorption is often incomplete and effectiveness is unpredictable.
