Final answer:
The strength of medication decreases based on the drug's half-life, which varies from drug to drug. This affects dosing frequency, with some drugs needing multiple doses per day and others only one. The drug could be dose dependent or time dependent.
Step-by-step explanation:
The strength of medication decreases by specific rates each hour it is in the patient's system. These rates can be explained by the medication's half-life, which is the time required for the concentration of the drug to reach half of its original value. Drugs with a shorter half-life, such as those with only 1 hour, must be taken multiple times a day. In contrast, drugs with a longer half-life of over 12 hours can sometimes be taken only once per day. It is also important to consider whether a drug is dose dependent, performing better with high levels for a short time, or time dependent, requiring maintained levels over an extended period.