Question

Read the medication labels where available, and calculate the number of tablets or capsules necessary to provide the dosage ordered. Include the label on your answer. Order: Retrovir \(0.2 \mathrm{~g}\) p.o. ti.d. Available: Retrovir capsules labeled \(100 \mathrm{mg}\) ______.

Short answer

6 capsules per day.

Step-by-step solution

Convert Ordered Dosage to Milligrams

The doctor's order is for Retrovir at a dosage of \(0.2 \text{ g}\). Before calculating the number of tablets needed, convert this amount to milligrams. Since \(1 \text{ g} = 1000 \text{ mg}\), \[0.2 \text{ g} = 0.2 \times 1000 \text{ mg} = 200 \text{ mg}\]

Determine Number of Capsules Per Dose

The medication label states that each capsule contains \(100 \text{ mg}\) of Retrovir. To find out how many capsules are needed to deliver one dose of \(200 \text{ mg}\):\[\text{Capsules per dose} = \frac{200 \text{ mg}}{100 \text{ mg per capsule}} = 2 \text{ capsules}\]

Calculate Total Daily Capsules

Since the order specifies the medication should be taken three times a day (t.i.d.), multiply the number of capsules per dose by three:\[\text{Total daily capsules} = 2 \text{ capsules per dose} \times 3 = 6 \text{ capsules per day}\]

Key concepts

Medication Label Reading

Understanding how to read a medication label is crucial for ensuring proper dosage calculations. Medication labels provide valuable information, including the name of the drug, dosage strength, and form of the medication. For our given task, the available Retrovir capsules are labeled with a strength of \(100 \text{ mg}\). This tells us that each capsule contains exactly \(100 \text{ mg}\) of Retrovir.

To accurately interpret the label, follow these steps:

• Check the Drug Name: Confirm you are examining the correct medication. Errors can occur if drugs with similar names are confused.
• Identify Dosage Strength: This is often expressed in milligrams (mg), micrograms (mcg), or grams (g). In this case, it is \(100 \text{ mg}\) per capsule.
• Confirm Medication Form: Note whether the medication is in solid form (tablets or capsules) or liquid. Our task involves capsules.

Efficient label reading helps in determining how many capsules are required per dosage and per day.

Unit Conversion

Unit conversion is an essential skill in accurately calculating medication dosages. Often, medication orders are given in a different unit than what is available on the label. In our example, the order is for \(0.2 \text{ g}\) of Retrovir, but the available capsules are labeled in milligrams (mg).

Here's a simple conversion process:

• Understand the Conversion Factor: Remember that \(1 \text{ g} = 1000 \text{ mg}\).
• Perform the Conversion: Multiply the gram (g) dosage by the conversion factor to convert it to milligrams (mg). For instance, \(0.2 \text{ g}\) converts to \(0.2 \times 1000 = 200 \text{ mg}\).
• Use Accurate Calculations: Ensures that no dosage errors occur, achieving patient safety.

Converting units correctly ensures you can match the medication ordered with the medication you have available.

Daily Dosage Interpretation

Interpreting a doctor's prescription for daily medication dosing involves understanding the frequency and total intake required over a day. In this task, the medication order specifies a dosage frequency known as "t.i.d." This stands for "ter in die," which means three times a day.

To determine daily dosage:

• Calculate per Dose Requirement: Find out how many units you need for a single dose. Based on our converted order, \(200 \text{ mg}\) per dose requires \(2\) Retrovir capsules since each provides \(100 \text{ mg}\).
• Multiply by the Frequency: Since the medication is to be taken three times each day, multiply the number of capsules per dose by three. Hence, \(2 \text{ capsules per dose} \times 3 = 6 \text{ capsules per day}\).
• Ensure Regular Timing: Spread out doses equally through the day to maintain a consistent therapeutic level in the body.

Understanding daily dosage interpretation ensures that the patient receives the intended therapeutic effect without under or overdosing.