Neuropharmacology - Principles

What is pharmacology?

The study of drugs and their effects on biological systems

What is neuropharmacology?

The branch of pharmacology focused on how drugs affect the nervous system

what is a xenobiotic?

A substance foreign to the body that is introduced into the system

What is a pharmaceutical?

A chemical substance used to diagnose, treat, or prevent disease

what is a neuroactive xenobiotic?

A foreign substance that specifically affects the nervous system

What does pharmacokinetics study?

How the body handles and interacts with a drug

What does “ADME” stand for in pharmacokinetics?

Absorption

Distribution

Metabolism

Excretion/Elimination

What are the main methods of drug absorption?

• Oral

• Intravenous

• Topical/dermal

• Intramuscular (under muscle)

• Subcutaneous (under skin)

• Sublingual (under tongue)

• Intraperitoneal (abdominal cavity)

• Inhalation

• Intranasal

• Rectal/suppository

• epidural

• intracranial

Which absorption method bypasses the GI tract but uses blood vessels under the tongue?

Sublingual absorption

Which drug administration route delivers substances directly into the abdominal cavity?

Intraperitoneal

what is a key advantage of oral drug administration?

Ease of use an patient compliance

what is a disadvantage of oral drug administration?

Slower absorption and variable dose timing/amount into the bloodstream

Can oral drug administration be reversed?

Yes, it is somewhat reversible before full absorption

What is the main advantage of intravenous (IV) administration?

Fastest absorption and controlled dosing

what is a limitation of IV administration?

Requires a professional to administer and is non-reversible once delivered.

what are advantages of transdermal drug administration?

Ease of use and patient compliance

what are disadvantages of transdermal drug administration?

Slower absorption, somewhat reversible before full absorption, and variable dose timing/amount depending on the person

Which absorption method gives the fastest rise in plasma concentration?

Intravenous (IV)

Which absorption method maintains the most stable plasma concentration over time?

Transdermal

Which absorption method shows variable peaks in plasma concentration depending on dose timing?

Oral administration

What defines the “therapeutic range” in pharmacology graphs?

The concentration window where the drug is effective without being toxic

Why might oral administration require multiple doses in a day?

Because plasma concentration fluctuates with variable absorption and metabolism

What drug is commonly prescribed for ADHD and narcolepsy? 

Methylphenidate 

What clinical issue is associated with methylphenidate use?

Acute tolerance (reduced effectiveness after repeated doses in a short period)

What are examples of methylphenidate formulations?

Ritalin (immediate-release), Ritalin LA (extended-release), Concerta (long-acting), Daytrana (transdermal patch).

Why are different formulations of methylphenidate developed? 

To control the rate of absorption, extend therapeutic effects, and reduce dosing frequency 

What is the benefit of transdermal methylphenidate (Daytrana)?

Provides steady drug delivery over hours, improving compliance and reducing fluctuations

What is the main limitation of immediate-release methylphenidate?

Short duration of action, requiring multiple doses per day 

How does concerta differ from other formulations of methylphenidate? 

It maintains plasma concentration within the therapeutic range for the longest duration 

Why are extended-release and long-acting formulations clinically useful? 

They improve patient compliance, reduce fluctuations in drug levels, and lower the risk of acute tolerance 

What is the therapeutic window in relation to methylphenidate formulations?

The plasma concentration range where the drug is effective but not toxic

What is Concerta’s brand name drug?

Methylphenidate 

What is unique about Concerta’s dosage form 

It provides a sustained and ascending drug release over a prolonged period 

What does concerta maintain therapeutic plasma levels?

By combining an initial immediate-release portion with a sustained-release mechanism

How does Concerta differ from immediate-release methylphenidate dosing schedules? 

Concerta maintains therapeutic effects with one dose per day, while immediate-release requires multiple doses every few hours 

What is the clinical benefit of Concerta’s ascending release profile?

It reduces fluctuations in drug levels, helps maintain consistent symptom control, and lowers the risk of side effects from peaks and troughs

In plasma concentration studies, how does Concerta compare tomultiple immediate-release doses?

Concerta produces a smoother, sustained curve while immediate-release causes repeated sharp peaks and drops

What is a product monograph? 

An official document that provides detailed prescribing and labeling information about a drug 

Who is the prescribing information in a product monograph intended for?

Physicians and other healthcare professionals

Who is the labeling information in a product monograph intended for?

Patients

Why are product monographs important?

They ensure safe and effective use of medications by providing standardized information for both prescribers and patients 

After ingestion, what organ processes xenobiotics before they enter systemic circulation? 

The liver, via portal blood 

What are the main elimination pathways for xenobiotics? 

Feces, urine, and expired air 

Which compartments can xenobiotics distribute into once in the blood and lymph?

Extracellular fluid, fat, other organs, soft tissues, bone, and the brain

What is the step-by-step pathway for an oral xenobiotic to the brain?

1. Ingestion → GI tract

2. Transport via portal blood

3. Processed in the