The physician has ordered Zantac elixir 75 mg PO bid for heartburn.

The medication is supplied in 15 mg/mL. How many milliliters will the nurse administer? (Shade CUP #1 to correct dose & LABEL CORRECTLY TO RECEIVE CREDIT)

Choice A rationale

Ordering a trough level 4 hours before the next scheduled dose would likely result in an inaccurate reading. The trough level represents the lowest concentration of a drug in the bloodstream, typically occurring just before the next dose, ensuring that the drug concentration remains within the therapeutic range to exert its pharmacological effect.

Choice B rationale

Obtaining a trough level 24 hours after the drug was given is too late and would not provide an accurate assessment of the drug's lowest concentration before the subsequent dose. By this time, depending on the drug's half-life, the concentration may be significantly lower or undetectable, making it irrelevant for therapeutic monitoring.

Choice C rationale

The trough level of a medication is measured to ensure that the drug concentration remains above the minimum effective concentration and below toxic levels. Collecting the blood sample 30 minutes before the administration of the next dose allows the drug to reach its lowest concentration in the systemic circulation, providing an accurate representation of the drug's true trough level.

Choice D rationale

Measuring the drug level 1 hour after the medication has been infused would represent a concentration much closer to the peak level, not the trough. The peak level indicates the maximum drug concentration, typically occurring shortly after administration or infusion, and is used to assess for potential toxicity or adequate absorption.

Choice A rationale

Partially withdrawing and redirecting the needle after aspirating blood significantly increases the risk of tissue trauma, pain, and the formation of a hematoma at the injection site. Furthermore, there is a risk of inadvertently injecting medication into a blood vessel or the interstitial tissue, which could lead to complications such as nerve damage or localized irritation.

Choice B rationale

Aspirating blood indicates the needle tip has entered a blood vessel. Administering medication intravenously when an intramuscular injection is intended can have serious systemic consequences, including rapid absorption and potential adverse drug reactions or toxicity. Therefore, the safest action is to withdraw the needle, discard the contaminated medication, and prepare a new dose to ensure proper drug delivery.

Choice C rationale

Administering the drug despite aspirating blood significantly increases the risk of injecting the medication directly into a blood vessel (intravascular injection) rather than the muscle. This can lead to rapid systemic absorption, potentially causing adverse effects or toxicity, and may also result in a larger, more painful hematoma and delayed drug action.

Choice D rationale

Continuing to administer the drug after aspirating blood, regardless of the injection speed, is dangerous because it confirms the needle's placement within a blood vessel. Intravascular administration of an IM medication can lead to immediate systemic effects, allergic reactions, or drug overdose, bypassing the intended slower absorption rate of muscle tissue, and increasing risk of complications.