Pharm Lecture 2 + Midterm Prep

Pharmacodynamics

Is the study of biologic, chemical, and physiologic interactions of a particular drug within the body


Responsible for: therapeutic affects, and sometimes it's adverse effects

study of biologic, chemical, and physiologic interactions of a particular drug within the body:

Pharmacodynamics

Responsible for therapeutic affects & sometimes it's adverse effects?

Pharmacodynamics

Receptor Theory is what?

Drugs act through receptors to produce or block a response.
The better a drug fits at the receptor site, the more biologically active it is

**like a key fitting into a lock.

3 types of receptor reactions:

1. binding to a receptor with either stimulates or inhibits a reaction
(ie: agonist, antagonist)

2. Binding can change the permeability of cell membrane.
Ie: Ca+ Chanel

3. Can release, or activate neurotransmitter to activate a response
Ie: direct or indirect

Agonist drug molecules do what:

Stimulate the cell to act!

Antagonist drug molecules do what:

-Block something else from attaching and causing a fat

designed to inhibit or block an agonist from activating a receptor

direct acting drugs

directly stimulate receptor; causing a reaction

Indirect acting drug

drug does not bind to receptor;

Instead, the ID drug stimulates a hormone/ neurotransmitter to be released from our system.
That neurotransmitter (norepinephrine or acetylcholine) will then bind to the receptor causing a reaction.

Acetylcholine: parasympathetic
Norepinephrine

What does continual stimulation from an agonist do?

Continue stimulation from an agonist. We usually make the drug less effective.

-as a result from this, the patient will usually need an increase in the dose, or different medication altogether.

Ie: high tolerance

What does continue a blockage from an antagonist usually do?

If you have a drug that's blocking the receptor from anything else... Once that antagonist is eventually removed:,that receptors going to be really sensitive (rebound effect)

rebound effect

An antagonist been removed from a receptor, that receptor is going to be really sensitive (high effect of the drug)

Adrenergic receptors:

Receptor sites for the sympathetic!

cholinergic receptors:

Parasympathetic nervous system!

Beta blockers are always what receptor?

Beta receptors are always Adrenergic (sympathetic!)

B1 blockers affect what organ?

heart

B2 blockers affect what organ?

lungs

What will the sympathetic nervous system do to the coronary blood vessels?

dilate

What will parasympathetic nervous system due to the G.I

It will increase the G.I. (Rest & digest)

B1 Adrenergic Antagonist receptor:

Decrease heart rate

B1 Adrenergic agonist receptor:

Increase heart rate

B2 adrenergic agonist receptor:

Increase respiration rate

B2 adrenergic antagonist receptor:

Decrease respiratory rate

B2 cholinergic agonist receptor:

Will relax the airway for COPD
(Chronic obstructive pulmonary disease)

What do calcium channel blockers due to blood pressure?

Lower it

Direct & indirect acting drugs:

Direct acting drugs will directly stimulate receptor

Indirect acting drugs, will stimulate Neurotransmitters to be released and attach to receptor site

Variables that affect drug actions (there's 4)

1.dosage

2.route of administration

3.drug-diet interactions

4.drug-drug interactions

Patient related variables: age, gender, body, weight, genetics, ethnicity, pre-existing conditions, physiological factors

serum drug level

Measurement of the amount of a drug in the blood at a particular time

This is to prevent a toxic amount of drug

minimum effective concentration

(MEC)

The level of the drug needed in the body to produce an effect
• largely determined by drug does, and how well it's absorbed into the bloodstream

• the strength of the response to a drug increases proportionately as more drug is given

potency and efficacy

Potency: the amount of a drug that must be given in order to produce a particular response

Efficacy: how well a drug produces its desired effect

Maintenance VS loading dose

-Maintenance dose: daily dose!
• the dose that is given consistently overtime to keep and/or tissue levels at a constant level (steady state)
Ie: birth control


-Loading dose - larger than usual dose to reach a therapeutic affect quicker

Maintenance dose

the dose of drug that maintains or keeps the drug in the therapeutic range

Ie: birth control

Loading dose

Larger than usual dose to reach a therapeutic effect quicker

How many days does it take to accomplish a steady state?

4 - 5 half lives

therapeutic index

The difference between an effective dose and a toxic dose

narrow therapeutic index:

small differences in drug dose or blood concentration can be fatal

When the amount of drug dose that needs to be taken by the patient is very close to the amount of the drug dosage that can kill a patient.

Ie: digoxin

What is one way that we determine the safety of a drug?

We compare the effective dose of a drug with the lethal dose of a drug. This process is called the 'therapeutic index'

How do we measure the therapeutic index of serum drug levels?

**peaks and troughs

As a drug level within the body increase, the patient is more likely to experience adverse effects from drug therapy

To help determine whether drugs does a sufficient to be in the therapeutic range, but not so high as to cause adverse effects, blood levels of the drug are often measured

drug-drug interactions:

Action of a drug may be increased or decreased by its interaction with another drug

• displacement (One drug competes with another drug for binding sites)

-Antidotes
-Activation of P450 system by inducers (to increase metabolism)

drug-drug example

Antidote

Displacement

Drug example of highly protein bound

Furosemide

What to assess for furosemide

Albumin!!!! Furosemide is VERY highly protein bound

⭕️⭐️What is the antidote for digoxin?

Digoxin immune Fab (Digibind)

⭕️⭐️What is the antidote for enoxaparin?

Protamine sulfate

⭕️⭐️antidote for morphine

Naloxone (Narcan)

⭕️⭐️ Insulin antidote

glucagon, glucose, epinephrine

How to reduce drug-diet interactions:

Giving medication one hour before or two hours after a meal can minimize drug diet interactions that decrease drug absorption

Ie: Grapefruit

An adverse effect may result from?

-too much of a therapeutic effect

-other pharmacodynamic effects of the drug

* every drug can produce adverse effects

Blackbox warning

The strongest warning, the FDA can give to consumers to warm about serious or life, threatening adverse effects

Ie: antidepressant, non-opioid, analgesics and immediate release, opioid analgesics

drug allergy cause

Occurs when the body forms antibodies to a particular drug response exposed to drug

Most serious: anaphylaxis

idiosyncratic response

strange, unique, or unpredicted response to a drug

Ie: taking Benadryl, and getting hyper

Treatment goals for drug overdose

Start treatment as soon as possible

Supporting stabilizing vital function

Preventing further damage on the toxic agent by reducing absorption or increasing elimination

Administering antidote when available

True or false, all drugs have some type of adverse effect?

True

Calcium channel antagonist (change in permeability)

Slows movement of calcium into cells of hearts/blood vessels

Calcium channel antagonist will block the flow of calcium (what makes the heart contract) into the heart.
Slowing down the influx of calcium will make it easier for the heart to pump the us dilating the arteries.

Dilating arteries will then decrease blood pressure.

Drug diet

Give meds one hour before
Or,
Two hours after a meal/anticoagulant/vitamin K/grapefruit juice

How do we maximize therapeutic results?

Administer drugs in a way that we cannot absorption

Administer drugs, an appropriate time

Monitor lab values

How do we minimize adverse effects?

Know the allergies

Know the contraindications

Administer safely

Monitor patient and labs

Withhold if necessary

Report adverse effects

Modify administration techniques (crushing pills)

Implement appropriate assessment to detect onset of adverse effects

Removing/drawing up medication from a vial

1. Uncapped syringe.

2. Drawback plunger to total amount that is going to be drawn up.

3. Put syringeIn vial, push all the air into the vial

4. Flip syringe & vial upside down, draw up medication to desired amount.

5. Use various techniques to remove air bubbles.

What is the best practice for giving medication's?

Rights of medication administration times three

Elements of medication order

Know medication administration Steps

How do drugs work?

Buy interfering with the enzyme cascade system P-450

Either by inducing, or inhibiting metabolism

When is single step in the enzyme? Cascade is blocked, the normal cell function is disrupted

first pass effect

Drugs given PO may be extensively metabolized before reaching systemic circulation

Clearance

Rate at which drug molecules disappear from the circulatory system

Affected by factors, such as gender

Renal excretion, and hepatic metabolism are both major modes of clearance

Renal disease labs

BUN and creatinine

UPS

Reviews and sets standards for the

Revise every five years

Geriatric considerations with absorption

Les gastric acid

Slow, gastric emptying

Slowed peristalsis

Reduce blood flow in G.I I don't know I'm just going over all of this

Geriatric considerations with distribution

Decreasing lean body mass

Increase in fat

Reduction in total body water content

Reduce protein binding sites due to aging liver

Displacement

To highly protein bound drugs, can just place one another

Geriatric consideration with metabolism

Aging liver \= decrease in size & mass \= decrease in blood flow \= decreasing metabolism

Geriatric consideration with excretion

Aging leads to greater incidence of toxicity

Lowest possible does to start

MEC

minimum effective concentration

Syrup, elixir , emulsion

Syrup and elixir absorbs the fastest

Emulsion solutions, usually oil absorb the 2nd fastest

In a hospital, breakfast, lunch, and dinner, or generally given at what times

0800

1200

1700

Health Status

Overall health of patient

S/s that digoxin is toxic?

-abdominal pain

- Anorexia

-Visual disturbances/seeing halos

Bradycardia

What medication will be assessed for bleeding

Enoxaparin

What medication's do we need to assess for hypokalemia

Digoxin, and furosemide

What medication's to be assessed for dehydration?

digoxin & furosemide

Timeframe available to give meds?

0900 - 2200

30 minutes before meal or 30 minutes after meal is best for all meds, unless indicated otherwise

Best place to administer enoxaparin

Subcut in love handles

How do you know if digoxin is working?

Decreased edema, auscultation, lungs, breathing easier

How do you know if furosemide is working?

Urine output
BUN/Cr levels
ALT/AST
Input/output

What do you assess for digoxin?

AP for 1 minute before administering to make sure that BP is above 60 bpm

electrolytes (toxic level will show increase in calcium & decrease in MAG & K)

serum dig levels (bc height alert drug)

BUN/Cr levels

ALT/AST

What do you assess for furosemide?

SBP

How to read an insulin sliding scale

Refers to the progressive increase in the pre-meal or nighttime insulin dose, based on predefined blood glucose range

Sliding scale, insulin regimen, approximate daily insulin requirements

When using a sliding scale, eat the same amount of carbohydrates at each meal. In other words, well, the foods may change, the time and the carbohydrate content of the meal should not vary.

When mixing insulins, does regular or NPH go first?

Regular insulin is drawn up first

Where is best to give insulin?

Abdomen

Must rotate subcut sites, giving the same spot overtime can cause lipodystrophy - this causes lumps or invitations that can interfere with insulin absorption

FYI, changing sites from back of arm to thighs will also change absorption

Processing medication administration we giving insulin, which is a high alert medication??????

Have another nurse check

Subcut volume

1 mL

Subcut gauge

25-30

Subcut length

3/8 - 1inch

Subcut most common length

3/8 - 5/8

subcut sites

- outer aspect of upper arm
- abdomen (5in from belly button)
- anterior aspect of thigh
- upper ventral area
- dorsogluteal area

Subcut angle

45-90 degrees

IM volume

1-4ml

IM aqueous Guage

20-25

IM oil based solution needle gauge

18 -25

IM vastus lateralis needle length

5/8 to 1.5


Putter thigh/superior

IM deltoid needle length

5/8 to 1 inch


Shoulder

IM ventrogluteal needle length

1.5 inches

Least desired location

Side of butt/superior

QSEN

Quality and Safety Education for Nurses