By Terry Spencer, DVM
(Fair Warning: This blog post includes MATH! If you are math phobic, please relax. There is no test at the end!)
My son is learning to cook. After one memorable mistake, he learned the difference between a teaspoon (t) and a tablespoon (T) of salt. That tiny difference in
measurement was very noticeable in the recipe. Thus, he learned that accuracy can avert disasters. I hope he applies that lesson to many other aspects of life.
Accuracy is vitally important for preventing medication errors. You certainly wouldn’t want your veterinarian to make any errors in dosing your pet’s prescriptions. Because it is so easy to transpose a number or misread a prescription, medical professionals have multiple safeguards in place to help prevent dosing errors. Quality control systems include requiring two staff members to approve a prescription, counting pills twice, and completing annual continuing education courses in pharmacy rules and regulations. Safeguards also include training staff to answer the 4R’s before giving medications; 1. Is this the right drug to give? 2. Is this the right patient? 3. Is it the right amount to administer? 4. Is this the right route? Math is very important for dosing medications accurately. Calculating a correct dose of medication requires basic algebra. Multiple times each day I convert pounds (lbs) to kilograms (kg), and then calculate the number of milligrams (mg) or millilitres (ml) required to give an animal based on the strength of the drugs I have available to use.
For example, to give a 15 mg/kg dose of antibiotic to a 50 lbs dog, I use the following formula:
(50# / 2.2 lbs/kg) 15 mg /kg = 340 mg dose to give. So if I have a 100 mg/ml solution to use, then I need 340 mg/100 mg/ ml = 3.4 ml.
I don’t guess. I do the math each time. No shortcuts allowed. And I usually triple check my calculations because I worry about making an error. After
all, a misplaced decimal point could mean the difference between drawing up 3.4 ml and 0.34 mls in a syringe. Only one dose is correct. The other dose could result in harm. The veterinary oath implores me to “First do no harm.” I take that seriously.
If I go through these gyrations each time I give a dose of medication to your pet, why would a pet owner be willing to take short cuts? It seems like a risky choice.
This week, I learned of just such a risky choice that resulted in a trip to the veterinary emergency room for two pets. It was a penny wise, but prescription foolish choice. The pet owner opted for “do-it-yourself” veterinary medicine to save some bucks. I don’t blame them for trying. Prescriptions are expensive.
This pet owner noticed that the active ingredient in popular prescription heartworm prevention for dogs was also sold over-the-counter in feed stores for use with livestock. The difference was that the dog medication is dosed in micrograms (mcg) and the livestock medication is dosed in milligrams (mg). The difference is a thousand fold. It is the same difference between a thousand dollars or a million dollars—just three little zeros. While the active ingredients in the two medications are the same, the strengths are completely different. The pet owner gave what looked to be a very tiny amount of the cheaper livestock drug to each dog. A few hours later, both dogs began to seizure and nearly died.
This was a disaster that could have been averted by simply checking with a veterinarian first. Perhaps the pet owner should go to my son’s cooking class.
A micro-ounce of prevention is better than mega-bucks spent in the emergency room because of a dosing error.
I’m happy to report that both dogs survived due to the skill of the emergency veterinarian who earned every penny that night. Let livestock take their medicine. And let small animals take their own medicine. Remember, accuracy can avert disasters.
practices at Bayonet Point Animal Clinic in Port Richey