Question

1. Know the pharmacodynamics on how medications effect the body from a cellular perspective

. 2. How are drugs classified and/or categorized, especially related to pregnancy?

3. What is the “therapeutic range” of a drug?

4. Develop an understanding of which systems of the body are most impacted by hypertension

.5. Know phenytoin (Dilantin): mechanism of action & adverse effects

6. Understand mechanism of action, general side effects and dietary considerations of the classes – SSRIs, MAOIs, anticholinergics

7. Know signs and symptoms of alcohol toxicity.

8. Understand the meaning of drug tolerance

9. How do local anesthetics work & what is the desired effect of general anesthesia?

10. How do opioid agonists work? How do beta-adrenergic agonists work?

Answer 1

1. Know the pharmacodynamics on how medications effect the body from a cellular perspective

Pharmacodynamics is the study of a drug's molecular, biochemical, and physiologic effects or actions. It comes from the Greek words "pharmakon" meaning "drug" and "dynamikos" meaning "power." All drugs produce their effects by interacting with biological structures or targets at the molecular level to induce a change in how the target molecule functions in regards to subsequent intermolecular interactions. These interactions include receptor binding, post-receptor effects, and chemical interactions. Examples of these types of interactions include

1. drugs binding to an active site of an enzyme,

2. drugs that interact with cell surface signaling proteins to disrupt downstream signaling,

3. drugs that act by binding molecules like tumor necrosis factor

2. How are drugs classified and/or categorized, especially related to pregnancy?

FDA CATEGORIES FOR DRUG USE IN PREGNANCY

Category A

Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy.

Example drugs: levothyroxine, folic acid, liothyronine

Category B

Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

Example drugs: metformin, hydrochlorothiazide, cyclobenzaprine, amoxicillin

Category C

Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Example drugs: gabapentin, amlodipine, trazodone

Category D

There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Example drugs: losartan

Category X

Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.

Example drugs: atorvastatin, simvastatin, methotrexate, finasteride

3. What is the “therapeutic range” of a drug?

The therapeutic range of a drug is the dosage range or blood plasma or serum concentration normally expected to achieve the desired therapeutic effect. This does not mean that patients may not achieve benefit at concentrations below the minimum threshold, or may not experience adverse effects if kept within the range.

4. Develop an understanding of which systems of the body are most impacted by hypertension

Hypertension is a condition that arises when the blood pressure is abnormally high. It occurs when the body’s smaller blood vessels (the arterioles) narrow, causing the blood to exert excessive pressure against the vessel walls and forcing the heart to work harder to maintain the pressure. Injury to blood vessels in the kidneys, brain, and eyes also may occur.

5. Know phenytoin (Dilantin): mechanism of action & adverse effects

Phenytoin is an anti-seizure medication used for preventing or treating generalized tonic-clonic seizures, complex partial seizures, and seizures occurring during or after neurosurgery. It may be used alone or with phenobarbital or other anticonvulsants.

Many adverse effects can occur during phenytoin therapy including:

dizziness,

drowsiness,

difficulty focusing ,

unsteady gate,

tiredness,

abnormal involuntary movements,

nausea,

vomiting,

constipation,

abdominal pain, and

loss of appetite.

Mechanism of Action

Phenytoin works by blockade of voltage-dependent membrane sodium channels responsible for increasing the action potential. Through this action, it obstructs the positive feedback that sustains high-frequency repetitive firing, thus preventing the spread of the seizure focal point.

6. Understand mechanism of action, general side effects and dietary considerations of the classes – SSRIs, MAOIs, anticholinergics

How Do SSRIs Work?

SSRIs work by enhancing the function of nerve cells in the brain that manage emotion. Information is communicated between your brain cells with signals. The chemical messengers that deliver these signals are called neurotransmitters. Serotonin is one type of neurotransmitter.

The possible side effects of these antidepressants include:

Insomnia

Headaches

Rash

Blurred vision

Drowsiness

Dry mouth

Agitation or nervousness

Feeling dizzy

Pain in the joints or muscles

Upset stomach, nausea, or diarrhea

Reduced sexual desire

MAOIs

Monoamine oxidase inhibitors (MAOIs) were the first type of antidepressant developed. They are effective, but they have generally been replaced by antidepressants that are safer and cause fewer side effects.

Use of MAOIs typically requires diet restrictions and avoiding certain other medications because MAOIs can cause dangerously high blood pressure when taken with certain foods or medications

Antidepressants such as MAOIs ease depression by affecting chemical messengers (neurotransmitters) used to communicate between brain cells. Like most antidepressants, MAOIs work by ultimately effecting changes in the brain chemistry that are operational in depression.

An enzyme called monoamine oxidase is involved in removing the neurotransmitters norepinephrine, serotonin and dopamine from the brain. MAOIs prevent this from happening, which makes more of these brain chemicals available to effect changes in both cells and circuits that have been impacted by depression.

MAOIs also affect other neurotransmitters in the brain and digestive system, causing side effects. MAOIs are sometimes used to treat conditions other than depression, such as Parkinson's disease.

Side effects of MAOIs

The most common side effects of MAOIs include:

Dry mouth

Nausea, diarrhea or constipation

Headache

Drowsiness

Insomnia

Dizziness or lightheadedness

Skin reaction at the patch site

What is an anticholinergic?

Anticholinergics are a type of medication that blocks the action of a neurotransmitter, a chemical messenger in the brain, called acetylcholine. Acetylcholine is responsible for transferring signals between certain cells that affect specific bodily functions.

The medication blocks acetylcholine from causing involuntary muscle movements in the lungs, gastrointestinal tract, urinary tract, and other areas of the body.

Possible side effects include:

confusion

hallucinations

memory problems

dry mouth

blurry vision

constipation

drowsiness

sedation

trouble urinating

delirium

decreased sweating

decreased saliva

7. Know signs and symptoms of alcohol toxicity.

Alcohol toxicity signs and symptoms include:

Confusion

Vomiting

Seizures

Slow breathing

Irregular breathing

Blue-tinged skin or pale skin

Low body temperature (hypothermia)

Passing out (unconsciousness) and can't be awakened

8. Understand the meaning of drug tolerance

Drug tolerance means that a person’s reaction to a drug decreases as they continue to use it. A person with a drug tolerance has to take larger doses in order to achieve the same effect as they did earlier in their drug use. Drug tolerance is not an addiction. It is simply the body becoming desensitized to the drug’s effects.

9. How do local anesthetics work & what is the desired effect of general anesthesia?

A local anaesthetic numbs a small part of the body. It is used when the nerves can be easily reached by drops, sprays, ointments or injections.

The local anaesthetic works by moving to the inside of the cell, then binding to the 'sodium channel' and so blocking the influx of sodium ions. This block stops nerve conductance and prevents further signals reaching the brain.

what is the desired effect of general anesthesia?

· Nausea and vomiting.

· Dry mouth.

· Sore throat or hoarseness.

· Chills and shivering.

· Confusion and fuzzy thinking.

· Muscle aches.

· Itching.

· Bladder problems.

· Dizziness.

10. How do opioid agonists work?

An agonist is a drug that activates certain receptors in the brain. Full agonist opioids activate the opioid receptors in the brain fully resulting in the full opioid effect. Examples of full agonists are heroin, oxycodone, methadone, hydrocodone, morphine, opium and others.

How do beta-adrenergic agonists work?

Beta adrenergic agonists or beta agonists are medications that relax muscles of the airways, causing widening of the airways and resulting in easier breathing. They are a class of sympathomimetic agents, each acting upon the beta adrenoceptors.