Principles of Pharmacology
1.9 Examining Effect
Onset, Peak, and Duration
Dosing considerations play an important role in understanding the effect that a medication may have on a client. During administration, the nurse must pay close attention to the desired effect and therapeutic response, as well as the safe dose range for any medication. The nurse should have an understanding of medication efficacy in order to ensure its appropriateness. If a nurse is provided different medication choices according to a provider’s written protocol, the nurse should select the option with the anticipated desired therapeutic response. Additionally, the nurse must be aware of the overall dose response based on the dosage selected.
Three additional principles related to the effect of a medication on a client are onset, peak, and duration.
Onset: the onset of medication refers to when the medication first begins to take effect
Peak : the peak of medication refers to the maximum concentration of medication in the body, and the point at which the client shows evidence of greatest therapeutic effect
Duration: the duration of medication refers to the length of time the medication produces its desired therapeutic effect
Consider this client care example and apply the principles of onset, peak, and duration: Gurmeet, a 67-year-old female client, who has just undergone hip replacement surgery earlier today, rings the call light to request medication for pain. She notes her pain is “excruciating, a definite 9 out of 10.” Her brow is furrowed, and she is grimacing in obvious discomfort. As the nurse providing care for Gurmeet, you examine her post-operative medication orders and consider the pain medication options available to you. In reviewing the various options, it is important to consider how quickly a medication will work (onset), when the medication will reach maximum effectiveness (peak), and how long the pain relief will last (duration). Understanding these principles is important in effectively relieving the client’s pain and constructing an overall plan of care.
Clinical Reasoning and Decision-Making Activity 1.9
- At 0500, your client, who had a total knee replacement yesterday, rates his pain while walking as 7 out of 10. Physical therapy is scheduled at 0900. The client has acetaminophen (Tylenol) 650 mg ordered every four hours as needed for discomfort. What should you consider in relation to the administration and timing of this client’s pain medication?
- Your client is prescribed NPH insulin to be given at breakfast and supper. As a student nurse, you know that insulin is used to decrease blood sugar levels in clients with diabetes mellitus. During report, you hear that the client has been ill with GI upset during the night, and the nursing assistant just informed you he refused his breakfast tray. While reviewing this medication order, you consider the purpose of the medication and information related to the medication’s onset, peak, and duration. When r