Question

Calculate the dosages for the problems that follow, and indicate the number of milliliters you will administer. Shade in the dosage on the syringe provided. Use medication labels or information provided to calculate the volume necessary to administer the dosage ordered. Express your answers to the nearest tenth except where indicated. Order: Methergine \(0.4 \mathrm{mg}\) IM \(\mathrm{q} 4 \mathrm{~h}\) for 3 doses. Available: Methergine labeled \(0.2 \mathrm{mg}\) per \(\mathrm{mL}\)

Short answer

Administer 2 mL per dose, totaling 6 mL for all doses.

Step-by-step solution

Understand the Medication Order

The order requires administering Methergine at a dose of 0.4 mg, delivered via intramuscular injection (IM), every 4 hours for a total of 3 doses.

Review the Medication Available

The available Methergine dosage form is labeled as containing 0.2 mg of the medication per 1 mL of solution.

Calculate the Required Volume for One Dose

To find out how many milliliters correspond to the ordered dose of 0.4 mg, set up a proportion based on the available concentration. If 0.2 mg is present in 1 mL, then 0.4 mg would require solving for x in the equation:\[ \frac{0.2}{1} = \frac{0.4}{x} \]

Solve the Proportion Equation

Cross multiply to solve for x.\[ 0.2x = 0.4 \]Divide both sides by 0.2 to isolate x:\[ x = \frac{0.4}{0.2} = 2 \]Thus, 2 mL is required to administer one 0.4 mg dose.

Express the Volume to the Nearest Tenth

Since the answer is 2 mL, it is already expressed to the nearest tenth (2.0 mL).

Total Volume for All Doses

Since there are three doses required, multiply the volume for one dose by the number of doses:\[ 2 \, \text{mL/dose} \times 3 \, \text{doses} = 6 \, \text{mL total} \]

Key concepts

Medication Administration

Administering medication effectively is critical in healthcare to ensure that patients receive the correct dosage every time. In this scenario, Methergine is to be administered via intramuscular injection, a method commonly used when immediate effect is needed. Administering medication through injection bypasses the digestive system, allowing the drug to enter circulation more quickly.
This method is often used for drugs that require rapid absorption or when oral medications are not an option.
When administering medication, it’s important to verify the order, identify the correct patient, and confirm the dosage and frequency. These steps are vital to prevent medication errors and ensure patient safety. Medical professionals often follow a set protocol, known as the "Five Rights" of medication administration.

• Right patient
• Right medication
• Right dose
• Right route
• Right time

By following these practices, healthcare providers minimize the risk of errors and improve healthcare outcomes.

Proportion Method

The proportion method is a useful mathematical approach for calculating dosages, especially when adjusting for different concentrations. It involves setting up a proportional relationship between the available dosage form and the desired dosage.
This method is valuable for ensuring accurate medication administration, which is crucial in preventing overdoses or underdoses.
In the exercise, we used the proportion method to calculate the amount of Methergine in milliliters needed to fulfill the ordered 0.4 mg dosage. We set up the proportion:\[ \frac{0.2}{1} = \frac{0.4}{x} \]This states that 0.2 mg is contained in 1 mL, and we need to find how many milliliters (x) are needed for 0.4 mg.
By cross-multiplying and solving for x:\[ 0.2x = 0.4 \]Dividing both sides by 0.2 gives:\[ x = 2 \text{ mL} \] Thus, solving this proportion helps in correctly calculating the dosage required for safe administration.

Intramuscular Injection

Intramuscular (IM) injection is a route of administration widely used to deliver medication deep into the muscles. This method allows for quick absorption into the bloodstream due to the muscles’ rich blood supply.
In the scenario presented, Methergine is administered via an IM injection every 4 hours for three doses.
The IM injection technique requires precision and knowledge to minimize discomfort and potential complications for the patient. It involves:

• Using the correct needle size to ensure proper delivery.
• Identifying suitable injection sites like the deltoid or gluteus maximus muscles.
• Avoiding blood vessels and nerves to prevent injury.

Injecting slowly and withdrawing the needle at the same angle can reduce tissue damage. Proper post-injection care, observing for any adverse reactions, is a part of the process.

Pharmacology Education

Pharmacology education plays a pivotal role in understanding how drugs interact with the body and their therapeutic uses. It provides the foundation for safe and effective medication administration, as seen with Methergine in this exercise.
Pharmacology helps healthcare providers make informed decisions when it comes to prescribing medications, understanding dosages, and anticipating possible side effects or interactions.
This exercise highlights how pharmacology education influences practice by equipping providers with the necessary skills to calculate dosages accurately, choose appropriate administration routes, and understand the implications of medication choices.
Continuous education in pharmacology ensures that practitioners keep up with new drugs, evolving guidelines, and the latest safety standards to improve patient care outcomes.