function calculateBasicDosage() {
var D = parseFloat(document.getElementById('desiredDose').value);
var H = parseFloat(document.getElementById('handDose').value);
var Q = parseFloat(document.getElementById('quantity').value);
var resultDiv = document.getElementById('basicResult');
if (isNaN(D) || isNaN(H) || isNaN(Q) || H <= 0) {
resultDiv.style.display = 'block';
resultDiv.style.color = 'red';
resultDiv.innerHTML = "Please enter valid numeric values. Dose on hand cannot be zero.";
return;
}
var amount = (D / H) * Q;
resultDiv.style.display = 'block';
resultDiv.style.color = '#333';
resultDiv.innerHTML = "Amount to Administer: " + amount.toFixed(2) + " (Units/mL/Tabs)";
}
function calculateIVRate() {
var V = parseFloat(document.getElementById('ivVolume').value);
var T = parseFloat(document.getElementById('ivTime').value);
var DF = parseFloat(document.getElementById('dropFactor').value);
var resultDiv = document.getElementById('ivResult');
if (isNaN(V) || isNaN(T) || isNaN(DF) || T <= 0) {
resultDiv.style.display = 'block';
resultDiv.style.color = 'red';
resultDiv.innerHTML = "Please enter valid numeric values. Time must be greater than zero.";
return;
}
var rate = (V * DF) / T;
resultDiv.style.display = 'block';
resultDiv.style.color = '#333';
resultDiv.innerHTML = "Flow Rate: " + Math.round(rate) + " gtt/min";
}
function calculateWeightDose() {
var W = parseFloat(document.getElementById('weightKg').value);
var M = parseFloat(document.getElementById('mgPerKg').value);
var resultDiv = document.getElementById('weightResult');
if (isNaN(W) || isNaN(M)) {
resultDiv.style.display = 'block';
resultDiv.style.color = 'red';
resultDiv.innerHTML = "Please enter valid numeric values for weight and dosage.";
return;
}
var totalDose = W * M;
resultDiv.style.display = 'block';
resultDiv.style.color = '#333';
resultDiv.innerHTML = "Total Required Dose: " + totalDose.toFixed(2) + " mg";
}
Dosage Calculation Practice Problems: A Complete Guide
Mastering drug dosage calculations is a critical skill for nursing students and healthcare professionals. Accuracy in these calculations ensures patient safety and effective treatment. This guide provides the essential formulas and practice problems often found in clinical exams and "dosage calculation practice problems with answers PDF" study materials.
The Three Main Formulas You Must Know
1. The Formula Method (D/H × Q)
This is the most common method for determining how many tablets or how much liquid volume to administer based on the provider's order.
- D (Desired Dose): The dose ordered by the physician.
- H (Dose on Hand): The strength of the medication available.
- Q (Quantity): The unit of measure the medication comes in (e.g., 1 tablet, 5 mL).
2. IV Drip Rate Calculation
When calculating manual IV infusions, you need to find the drops per minute (gtt/min). The formula is:
(Total Volume in mL × Drop Factor) / Time in Minutes = gtt/min
3. Weight-Based Dosage
Pediatric and high-alert medications are often calculated based on the patient's weight in kilograms.
Step 1: Convert lbs to kg (Weight in lbs ÷ 2.2).
Step 2: Multiply kg by the ordered dose (mg/kg).
Practice Problems with Answers
Problem 1: The doctor orders 500 mg of Amoxicillin. The pharmacy provides 250 mg capsules. How many capsules should you administer?
Answer: (500 / 250) × 1 = 2 Capsules.
Problem 2: Administer 1,000 mL of Normal Saline over 8 hours. The drop factor is 15 gtt/mL. What is the drip rate?
Steps: 8 hours = 480 minutes. (1000 × 15) / 480 = 31.25. Answer: 31 gtt/min.
Problem 3: A child weighing 20 kg is ordered to receive 15 mg/kg of Acetaminophen. What is the total dose?
Answer: 20 kg × 15 mg/kg = 300 mg.
Tips for Success
- Always double-check units: Ensure your "Desired" and "Hand" doses are in the same units (e.g., both in mg, not one in grams and one in mg).
- Round appropriately: Generally, round drops (gtt) to the nearest whole number and liquid mL to the nearest tenth, but always follow your specific facility or school policy.
- Re-read the question: Identify if the question asks for "per dose" or "per day."