PharmacologyObjectives

1. The student will be able to understand how medications are measured

2. The student will know what the FDA is and why they are necessary for safety

3. The student will know what the difference is between the Therapeutic dose and the lethal dose of a medication and some examples.

4.The student will understand the importance of knowing what drugs can be combined and where to find that information

5. The student will understand the different types of drug interactions.

It’s all about Metric

The metric system is used for drug dosages,measurement.

Teaspoons, Tablespoons, cups,ounces to pounds are the familiar measurements

milligrams, grams, kilograms are how things are measured in the medical world.

Easier than you think. Everything relates by a 10th, 100th or 1000th. Examples

Units of metric measurement

Quantity measured Unit Symbol Relationship

mass milligram mg 1000 mg= 1 gram

Gram g 1 kg= 1000 g

Kilogram kg metric ton=1000kg

Volume milliliter ml 1000 ml= 1 liter

Cubic centimeter cc 1 ml= 1 cc

Liter l 1000 l= 1 cm

Cubic meter cm

** 1 tsp= 5 ml 1 cup=250 ml

What dose of Motrin?

What dose of Motrin

Overview & UsesWhen your child isn't feeling well, bring them relief with Children's MOTRIN®. Its safety profile is supported by one of the largest and most rigorous children's clinical studies ever conducted. And, it lasts up to 8 hours. Children's MOTRIN® will help you both feel better.

Uses:Temporarily:Relieves minor aches and pains due to the common cold, flu, sore throat, headache and toothacheReduces fever

Naproxen, Aleve, NaprosynNaproxen 250 mg or 375 mg or 500 mg twice daily

Naproxen sodium

275 mg (naproxen 250 mg with 25 mg sodium) twice daily

550 mg (naproxen 500 mg with 50 mg sodium) twice daily

What dose of medication?What volume contains the dose you need?

If you have an ampoule of 500mg in 4ml, and you need 200mg, it can appear to be a daunting

calculation. The first step is to find out what volume contains 1mg (4/500) and then multiply it by

how many mg you want (200).

The easy way to remember this is the famous nursing equation:

‘What you want, over what you’ve got, times what it’s in’

In this instance:

200mg x 4ml / 500mg = 1.6ml

The common error here is to get it upside down, and divide what you’ve got by what you want. This

fortunately gives you a stupid answer, which is obviously wrong, in this case 10ml. You already know

that you need a fraction of an ampoule and not two and a bit ampoules, which highlights the error.

Oral vs parenteralDepends on chemical composition and how drug is metabolized.

Definition

Drug metabolism is the process by which the body breaks down and converts medication into active chemical substances/metabolites

Precautions

Drugs can interact with other drugs, foods, and beverages. Interactions can lessen or magnify the desired therapeutic effect of a drug, or may cause unwanted or unexpected side effects. There are thousands of possible drug-to-drug and drug-to-food interactions, and many medications and supplements are contraindicated (not recommended) under certain conditions or in patients with specific diseases and disorders. This is why it is imperative that patients always keep their physician fully informed about all drugs and dietary supplements (including herbal remedies) they are taking.

Drug Metablolism Definitions

The Liver-,The primary site of drug metabolism, the organ that plays a major role in metabolism, digestion,detoxification, and elimination of substances from the body. A solid organ located on the right in the upper abdomen. It plays a major role in metabolism, digestion, detoxification, and elimination of substances from the body.

Enzymes-organic substances (proteins) composed of amino acids that trigger and regulate chemical reactions in the body. There are over 700 identified human enzymes

Metabolites- Substances produced by metabolism or by a metabolic process. They are then bound to other substances for excretion through the lungs, or bodily fluids such as saliva, sweat, breast milk, and urine, or through reabsorption by the intestines.

Definitions continuedthe kidneys-The primary mode of excretion for drug metabolites (where urine

comes from.) We have 2 located both sides of mid backCytochrome P-450-The family of liver isoenzymes that are crucial to drugmetabolismMetabolism-the sum of all the physical and chemical processes occurring in

the body to organize and maintain lifeCatabolism- a process of metabolism that breaks down complex substances

into simple ones.Cirrhosis-Liver disease characterized by the widespread disruption of the

normal liver structure and function.CNS Depressant- Anything that depresses, or slows, the sympathetic

impulses of the central nervous system (i.e., respiratory rate, heart rate).

Drug metabolismDrugs can interact with other drugs, foods, and beverages.

Interactions can lessen or magnify the desired therapeutic effect of a drug, or may cause unwanted or unexpected side effects.

There are thousands of possible drug-to-drug and drug-to-food interactions, and many medications and supplements are contraindicated (not recommended) under certain conditions or in patients with specific diseases and disorders.

This is why it is important that patients always keep their physician fully informed about all drugs and dietary supplements (including herbal remedies) they are taking.

Drug Metabolism PhysiologyThe primary site of drug metabolism is the liverEnzymes in the liver are responsible for chemically changing drug

components into substances known as metabolites. Metabolites are then bound to other substances for excretion through the

lungs, or bodily fluids such as saliva, sweat, breast milk, and urine, or through reabsorption by the intestines. The primary mode of excretion is through the kidneys.

The family of liver isoenzymes known as cytochrome P-450 are crucial to drug metabolism. These enzymes (labeled CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) have a catabolic action on substances, breaking them down into metabolites. They also act to lower the concentration of medication in the bloodstream.

Drug Interactions: Definition

“The pharmacologic or clinical response to the administration of a drug combination different from that anticipated from the known effects of the two agents when given alone”

Tatro DS (Ed.) Drug Interaction Facts. J.B. Lippincott Co. St. Louis 1992 Types of Drug Interactions

Pharmacokinetic- What the body does with the drug

- One drug alters the concentration of another by alteringits absorption, distribution, metabolism, or excretion

- Usually (but not always) mediated by cytochrome P450 (CYP) - Can depend on absorption (GI motility, pH) Distrubution (transport proteins) Metabolism,

(CYP450). Elimination(renal Kidney function)

Pharmacodynamic drug interactions

Synergistic combinationsPhamacologic (drug) effect is greater than the summation of the 2 drugssometimes beneficial and sometimes harmfulBeneficial: aminoglycoside +penicillin cell wall breakdown by PCNHarmful: barbituates and alcohol alcohol enhances the effects of the barbituateAntagonistic combinations Pharmacologic effect is less than the summation fo the 2 drugs Beneficial: Naloxone(Narcan) in opiate overdoseHarmful zidovudine + stavudine used in treating HIV one makes the other

ineffectiveAdditivity effect equals the summation of the 2 drugsBeneficial: Asprin + acetaminophen both work together to relieve pain betterHarmful: neutropenia with zidovudine + ganciclovir (HIV drugs) blood toxicity

Drug interactions*Drug interactions can occur when one drug inhibits or induces a P-450 that acts

on another drug. An example is nicotine, a drug contained in tobacco, and known to induce P-450s.

*Individuals with liver disease (ie: cirrhosis) may have insufficient levels of P-450 enzymes. As a result, the concentration of drugs metabolized by these enzymes remains high and can build up to toxic levels in the bloodstream

*certain medications and foods, such as grapefruit juice, can inactivate or lessen the metabolic activity of P-450s.

*The metabolic rate can vary significantly from person to person, and drug dosages that work quickly and effectively in one individual may not work well for another. Factors such as genetics, environment, nutrition, and age also influence drug metabolism; infants and elderly patients may have a reduced capacity to metabolize certain drugs, and may require adjustments in dosage.

Common drug interactionsWhat are some common drug interactions that you can think of?Are they harmful or beneficial?Example

What about illegal drugs? How do you know whats really in them if they are not controlled by the FDA? How do you know the therapeutic dose or the toxic dose?

Example Opiates. Legal vs illegal Suicide vs accidental overdose

Tylenol (acetaminophen)Example of a common medication that when taken as prescribed is very safe for

most people but if taken in higher doses or in combination with things islethal……Tylenol (acetaminophen) can purchase by itself or it is contained in some

prescription medications and other over the counter medications. Easy to ODWhy?The liver breaks down most of the drug into safe components that can be removed

from the body in the urine. However, a small amount of Tylenol is expected to be metabolized into a harmful by-product called NAPQI (which stands for N-acetyl-p-benzoquinoneimine). When Tylenol is taken in recommended doses, your body can quickly remove this toxic by-product in the urine. However, when the liver needs to suddenly metabolize overdose levels of Tylenol, too much of the toxic NAPQI is made and it starts to harm the main cells of the liver

Medication combinationsToday, more than 600 over the counter and prescription medications containtylenol (acetaminophen) Some examplesAlka-Seltzer Plus Liquid Gels Formula 44 cough syrup Butalbital

Anacin Midol Edocet

Cepacol nyquil Hycotab

Contac Robitussin Fioricet

Coricidin Sudafed Hydrocodone

Dayquil Midol lortab

Theraflu Excedrin Percocet

Dimetapp Zicam Vicodin

Dristan Vicks Oxycodone etc

IbuprofenAdvil, Motrin (ibuprofen) alternative pain, fever reducer. NSAIDS (non steroidal anti inflammatory drug) rarely affect the liver. Unlike

acetaminophen (Tylenol) most NSAIDs are absorbed completely and have negligible first-pass hepatic (liver) metabolism. In other words, the way NSAIDS are metabolized makes liver toxicity (hepatotoxicity) very rare.

It’s about the kidneys:

NSAIDs have important adverse effects on the kidney that you should know about. Here is the science

behind the problem. Ibuprofen and other NSAIDs inhibit prostaglandins, and that can cause a problem

because prostaglandins dilate blood vessels leading to the kidneys. Inhibiting prostaglandins may lead

to kidney ischemia (dead tissue from decreased blood flow) and thus acute kidney injury.

Dr. orders in school

PARENT/GUARDIAN SECTION * SECCION DE PADRE/GUARDIANI request that the school nurse, or designated staff member, administer the medication prescribed below, in accordance with the healthcare provider instructions.

I give my permission for the following medication information to be shared with school staff on a “need to know” basis. HEALTH CARE PROVIDER SECTION

Diagnosis for which medication is to be given during school hours:_______________________________

Is this condition Life Threatening? Yes / No *911 will be called whenever the student’s condition deteriorates

_ ________ __________ ___po_______ Beginning of school after breakfast_

Name of medication (1 per form): Dosage: Method of administration: Time o

Possible side effects:____________________________________________Emergency Action:____________________________or 911

When the parent requests may we give the morning dose of the above medication when forgotten at home? Yes / No

HCP Signature Date

PERMISSION TO ADMINISTER MEDICATION AT SCHOOL

Student: _______________________ __________Birthdate: __ _________Grade: _____

FDA Food and Drug Administration

FDA is responsible for protecting the public health by assuring the safety, efficacy and security of human and veterinary drugs, biological products, medical devices, our nation's food supply, cosmetics, and products that emit radiation.

FDA is also responsible for advancing the public health by helping to speed innovations that make medicines more effective, safer, and more affordable and by helping the public get the accurate, science-based information they need to use medicines and foods to maintain and improve their health.