If you want to find what the appropriate dosage of a drug is for your body weight, you need to follow these steps:
- Determine the dosage of the medication. Let's say the appropriate dosage of the active substance is 2 mg/kg of body weight.
- Weigh yourself. ...
- Multiply these two values to get the dose of medication in mg: 2 * 80 = 160 mg. ...
- What if your medication is liquid? ...
- Divide the dose by the medicine concentration to obtain the liquid dose: 160 / 2 = 80 ml.
Full Answer
How do you calculate dosage of a drug?
Drug Dosage Calculation Formulas. To calculate the number of tablets, use the following formula: Strength required / Stock strength = Number of tablet (s) required. Or another way this drug dosage formula can be expressed is: What you want / What you’ve got = Number of tablet (s) required.
What is meant by the strength of a drug?
The strength is the amount of drug in the dosage form or a unit of the dosage form (e.g. 500 mg capsule, 250 mg/5 mL suspension).
How do you calculate the number of tablets in a pill?
To calculate the number of tablets, use the following formula: Strength required / Stock strength = Number of tablet (s) required. Or another way this drug dosage formula can be expressed is: What you want / What you’ve got = Number of tablet (s) required.
What is the appropriate dosage of a drug for your weight?
If you want to find what the appropriate dosage of a drug is for your body weight, you need to follow these steps: Determine the dosage of the medication. Let's say the appropriate dosage of the active substance is 2 mg/kg of body weight. Weigh yourself.
How is medicine strength calculated?
However, quite often the strength of a drug is presented as a percentage, as described below: % w/v = percentage weight of a substance by volume measured in grams in 100 millilitres. % w/w = percentage weight of a substance by weight measured in grams in 100 grams.
How do you calculate medication dosages?
A basic formula, solving for x, guides us in the setting up of an equation: D/H x Q = x, or Desired dose (amount) = ordered Dose amount/amount on Hand x Quantity....Dimensional Analysis MethodThe clinician has 2 mg/mL vials in the automated dispensing unit.How many milliliters are needed to arrive at an ordered dose?More items...•
How do you calculate medication dosages based on weight?
Care must be taken to properly convert body weight from pounds to kilograms (1 kg= 2.2 lb) before calculating doses based on body weight....Example 2.Step 1. Calculate the dose in mg:18 kg × 100 mg/kg/day = 1800 mg/dayStep 3. Convert the mg dose to mL:1800 mg/dose ÷ 40 mg/mL = 45 mL once daily1 more row
How do you calculate mg per mL?
Divide the mass in milligrams by volume in milliliters to find concentration in mg/mL. For example, if you have 8,000 milligrams of sugar dissolved in 200 milliliters of water, work out 8,000 ÷ 200 = 40. The concentration of the solution is 40 mg/mL.
Why is it important to correctly calculate medication dosages?
Accurate pharmacy calculations prevent medical errors; underdosing a patient may lead to inadequate treatment, and overdosing a patient may lead to drug toxicity.
Why does weight matter for medication?
A patient's weight is important information because it is often used to calculate the appropriate medication dose. When medication errors arise due to inaccurate or unknown patient weights, the dose of a prescribed medication could be significantly different from what is appropriate.
What medications are based on weight?
Weight-based medicine doses are prescribed for children and adults with conditions where there is a wide range of optimal dosages. The most common examples are antibiotics, opioids, diabetes medications, and chemotherapy drugs.
Does medicine go by weight or age?
Measure liquid medication by weight, not age However, doctors say you should actually use your child's weight to determine the right dose. “We calculate all medicine for children based on their weight,” Dr. Platt says. “So if you have a very small 8-year-old child, you might want to give them a dose for a 4-year-old.”
What is mg m2 dosing?
Most drugs in children are dosed according to body weight (mg/kg) or body surface area (BSA) (mg/m2). Care must be taken to properly convert body weight from pounds to kilograms (1 kg= 2.2 lb) before calculating doses based on body weight.
How do you calculate ml per hour?
0:023:58Ex: IV Calculation - Flow Rate in Milliliters Per Hour - YouTubeYouTubeStart of suggested clipEnd of suggested clipWe take the total volume of the solution in milliliters or CCS and divide by the total number ofMoreWe take the total volume of the solution in milliliters or CCS and divide by the total number of hours to run.
How do you calculate injection dosages?
Use this formula for these types of questions: "mg/ml=%X10". Using this formula, multiply the percentage by 10. So 2.27% X 10 = 22.7 mg/mL. Side note- (if the percent concentration was 5% it would be 50mg/mL, if it was 10% it would be 100mg/mL, and so on.)
What is Young's rule formula?
[Age / (Age + 12)] x Recommended Adult Dose = Pediatric Dose Young's Rule can be applied to quickly approach a situation in which the patient's weight is unknown. Other approaches to pediatric dosing that also use age include Webster's Rule and Fried's Rule.
What is the SPL for drug strength?
In order to standardize the expression of active ingredients in drug listing Structured Product Labeling (SPL) submitted to FDA, the agency has adopted a series of automated validation rules to allow for certain expressions.
What is the denominator of a reconstituted powder?
Note that for powders that are reconstituted, the denominator is the volume following reconstitution if the amount is fixed. For example, if 10 mg of a powder in a vial is mixed with 5 ml of diluent, the strength is 10 mg in 5ml. If the reconstituted amount is not fixed, then the denominator is 1. For example, if 10 mg of a powder in a vial is mixed with 5-10 ml of diluent, the strength is 10 mg in 1 vial.
What does "w/v" mean in chemistry?
As w/v - mass (grams) of solute in a volume (100ml) of solution, like oral liquids
Is strength of active ingredient a percentage?
For example, the strength of active ingredient is not allowed to be included as a percentage value but can be a concentration of an amount of solute in an amount of solution: As w/w - mass (grams) of solute in mass (100 gm) of solution, like topical creams and ointments.
Does strength of active ingredients in a product need to be converted to w/w or w/v?
Exceptions to this rule are alcohol, medical gases and water. Strength of active ingredients in these products can be included in the SPL as v/v and does not need to be converted into w/w or w/v. In cases like alcohol, the value of density can fluctuate depending on the temperature.
Oral Dose
Cephalexin (Keflex) 750 mg P.O. every 12 hours is ordered. The pharmacy stocks 250 mg tablets. How many tablets should be administered per dose?
Intravenous (IV) Dose
An order for digoxin 0.5 mg IV daily is placed. Digoxin 0.25 mg/mL is available from the pharmacy. How many mL will you need to administer a 0.5 mg dose?
Subcutaneous Dose
Heparin 7500 units subcutaneous every 12 hours is ordered. The pharmacy provides a heparin vial with a concentration of 5000 units/mL. How many mL will you need to administer 7500 units?
What is the drug concentration?
Specifically, the drug concentration is defined in terms of one unit of solute contained in a total amount of solution or mixture. In this blog post, you will learn how to solve three NAPLEX type ratio ...
What is RxCalculations?
RxCalculations is a leading global educational service platform focused on developing top quality pharmaceutical calculations products to help prospective pharmacists and health care professionals all over the world resolve one of the biggest challenges related to their profession.
What episode of Pharmaceutical Calculations is NAPLEX?
In episode 6 of the pharmaceutical calculations podcast, you will learn how to solve three NAPLEX type ratio strength calculations questions. Special attention is given to properly analyzing each question and determining the best approach to solving them accurately and expeditiously. This episode was originally broadcast as a video on our YouTube channel: www.youtube.com/pharmaceuticalcalculationseasy
How many milliliters is x?
x is going to be equal to 25 grams times 1000 milliliters divided by one gram. The grams cancel out, and you're going to end up with 25,000 milliliters. But we don't stop here because the question says how many liters and so the next thing we want to do is do a quick conversion.
How many grams are in 40 milliliters?
So it actually means you have one gram in 40 milliliters. And what you want to figure out is how many grams will be required to prepare 120 milliliters. So you can go ahead and solve for our unknown which is x. So x is equal to one gram times 120 milliliters divided by 40 milliliters and x is going to be equal to 3 grams.
What does percentage strength mean?
Percent strength represents the number of grams contained in 100 mL of product and is very useful in pharmacy calculations.
Why is accurate calculation important in pharmacy?
Accurate pharmacy calculations prevent medical errors; underdosing a patient may lead to inadequate treatment, and overdosing a patient may lead to drug toxicity.
What is %v/v?
Percent Volume in Volume (v/v): Is the number of milliliters in 100 mL of solution and is expressed as %v/v. A liquid component in a liquid preparation would be calculated on a v/v basis.
What is the volume of IV?
Total IV Volume/Time (hour or minute) = mL per hour or minute
What is specific gravity?
Specific gravityrefers to the ratio of the weight of a substance to the weight of an equal volume of water at the same time.
How to add degrees C to degrees F?
Degrees C to degrees F: Divide by 5, then multiply by 9, then add 32
What is the amount of active ingredient per total weight of a substance?
Concentrationis the amount of active ingredient per total weight of a substance.
What is dose in medicine?
The dose is the amount of drug taken at any one time. This can be expressed as the weight of drug (e.g. 250 mg), volume of drug solution (e.g. 10 mL, 2 drops), the number of dosage forms (e.g. 1 capsule, 1 suppository) or some other quantity (e.g. 2 puffs).
Where are the instructions for a prescription for a medicine?
Dosage instructions are written on the doctor's prescription or hospital chart, and on the pharmacy label of a prescribed medicine. Dosage instructions are also found on the packaging and inserts of over-the-counter medicines.
What is the dosage regimen?
The dosage regimen is the frequency at which the drug doses are given. Examples include 2.5 mL twice a day, one tablet three times a day, one injection every four weeks. The total daily dose is calculated from the dose and the number of times per day the dose is taken. The dosage form is the physical form of a dose of drug.
How to determine the dosage of a drug?
Let's say the appropriate dosage of the active substance is 2 mg/kg of body weight. Weigh yourself. Let's assume you weigh 80 kg.
What does the dosage calculator do?
The dosage calculator finds what dose of a medication is appropriate for your weight. It can also recalculate the dosage expressed in mg/kg into doses of liquid medication.
What is an appropriate dose?
When treating a patient, or just taking a medication by yourself, we always need to wonder what is the exact dose of the drug we choose. And the truth is that we dose (or should dose) nearly everything in our life, from cooking dinner to taking medications! However, regarding drugs, there are certain different kinds of dosing that depend on the specific drug and/or the patient.
Why do we need to calculate pediatric doses?
This sentence still holds today. We know that every substance, especially drugs , may be toxic if given in an inappropriate dose. This is why we should perform our dosage calculations carefully and accurately. This is especially critical when administering drugs to children, as a slight mistake in the dose may cause a significant change in the effect of its action. The usage of a pediatric dose calculator seems to be a responsible choice that reduces the risk of a mistake!
How do doses differ?
The doses are different depending on the concentration of the drug's active compound in the serum. (e.g. Vitamin K antagonists, lithium) 5. The dosage of the drug depends on the patient's body weight. The dose of the drug depend on the weight of the patient.
What are the different types of dosing?
However, regarding the drugs, there are certain different kinds of dosing that depend on the specific drug and/or the patient. 1. One dosage. Drugs with one fix dosage are the easiest in use; you just take it and forget about it (e.g. vaccines). You don't need to use any dosage calculation formulas! 2.
What does "dosage" mean in medicine?
dose — Total amount of medication you need to take.
