ABSTRACT
Drugs are administered as a single dose usually for the management of acute medical conditions or transient symptoms. If rapid drug action is required such as in case of emergency or if the patient is unconscious, the drug can be administered intravenously. When the drug is administered orally, the rate of drug absorption usually determines the onset of drug effect. Due to drug elimination from the body, the effect of drugs administered as single dose subsides with time and repeated drug administration may be required if the symptoms persist. The plasma drug concentration ¥uctuates up and down during repeated intravenous (IV) or oral drug administration, which can lead to change in symptoms control when direct relationship exists between the drug effect and plasma drug concentration. So to maintain constant plasma drug concentration, the drug has to be administered as constant rate IV infusion.
