PHAR2330

Drug Information in Pharmacy Practice

Bilvick Tai
Lecturer, School of Pharmacy
Email: bwtai@cuhk.edu.hk
Date: Jan 8, 2025

Copyright © 2020. All Rights Reserved. Faculty of Medicine, The Chinese University of Hong Kong 1
 Learning objectives

• To understand the scope and give examples of drug information (DI) services

• To distinguish between primary, secondary, and tertiary resources in the

pharmacy field

• To understand the difference between patient education and consumer health

information

• To provide examples of appropriate DI resource(s) used for different

categories of DI questions

• Given a drug information request, be able to suggest the most appropriate

resource used for responding to the request

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 What is “drug information”

• The term “drug information” was developed in the early 1960s

• In 1962, the first drug information center was opened at the

University of Kentucky Medical Center in the US
o Purpose of this center:
❖ Provide comprehensive drug information for staff physicians, dentists,
and nurses
❖ Education of health professional students including medicine, dentistry,
nursing, and pharmacy students

• In 2018, there were 82 reported pharmacist-operated drug

information centers in the US

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 Drug information services

Examples of drug information services

Answer questions regarding medications from patients’ caregivers, and health
care professionals
Coordinate pharmacy and therapeutics committee activity
Develop and educate health care professionals on medication-use policies
Critically evaluate the literature to make formulary and patient-specific
decisions
Develop criteria/guidelines for medication use
Publish or edit information on appropriate medication use through
newsletters, journal columns, websites, email, social media, etc.
Provide education for health care professionals, students, and patients

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 Drug information services

Examples of drug information services (cont’d)

Analyse the clinical and economic impact of drug policy decisions
Manage medication-use evaluation and other quality assurance/improvement
activities
Manage drug shortages
Manage investigational medication use (e.g., institutional review board
activities, information for practitioners)
Consult on pharmacy informatics projects in the health care system setting
Develop clinical decision support tools for CPOE including order sets and alerts
Provide poison information

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 Drug information services
• Well-defined criteria are not established for using the titles of drug
information center/service

• Some centers specialize in a particular area of drug information,

and the name of the center may reflect that specific function, e.g.
o Center for Drug Evaluation and Research
o Center for Clinical Outcomes Research and Education
o Center for Drug Policy
o Drug Information Center
o Poison Control Center

• Providing drug information may be on a one-on-one basis or may

occur using a more structured approach

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 Drug information skills

Drug information skills for

answering questions using a systemic approach
1. Identify the requestor
2. Define the true question and information need
3. Obtain complete background information
4. Categorize the question
5. Perform a systematic search
6. Analyze the information
7. Disseminate the information
8. Document
9. Follow-up

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 Types of references

• Health care professionals must be

knowledgeable and proficient with the
different types of biomedical resources

• 3 types of information sources in

biomedical literature: primary, secondary,
and tertiary resources

• Definitions of the 3 types may vary

depending on discipline, and a reference
may serve as more than one type of
resource depending on the scenario

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 Tertiary resources (references)

• Contain information that has been filtered and summarized by the

author or editor to provide a quick and concise overview of a topic

• The most appropriate and efficient first step to finding information

before searching in other types of resources

• Examples: textbooks, compendia, clinical guidelines

• Some are available as electronically searchable online applications,

whereas online access for others is via e-books

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 Tertiary resources (references)
Common examples of tertiary resources:

Martindale: The Complete Drug

AHFS Drug Information
Reference/MedicinesComplete
ClinicalTrials.gov
Medscape
Drugs and Lactation Database
Micromedex
(LactMed)
Natural Medicines
Facts & Comparisons
Pediatric Injectable Drugs
ISMP Medication Safety Alert!
(The Teddy Bear Book)
Acute Care
Physicians’ Desk Reference
King Guide to Parenteral Admixtures
Stockley’s Drug Interactions
UpToDate / Lexidrug
USP-NF (United States Pharmacopeia and
National Formulary)

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 Tertiary resources (references)
Common examples of pharmacy textbook:

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 Tertiary resources (references)

• Benefits of tertiary resources:

o Convenient, easy to use, and are familiar to most practitioners
o Provide a fairly complete and concise overview of information available
on a specific topic
o Many are available in electronic formats

• Limitations of tertiary resources:

o Lag time associated with updating information
o Searching for specific terms in print references can be more challenging
o Lacking complete or detailed information
o Errors in transcription, human bias, incorrect interpretation of
information, or a lack of expertise by authors

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 Secondary resources (references)

• Mainly in the form of searchable databases that enable location and

retrieval of primary or tertiary resources

• Allows for more efficient and expedient searching for either primary
literature (e.g. a clinical trial) or a narrative review for a given topic

• Allows for finding additional resources and gain more insight on the
topic

• Most databases allow results to be restricted via use of limits or

filters
o E.g. language of publication, year of publication, type of article, or
type of journal where a publication is found

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 Secondary resources (references)
Common examples of secondary resources:

PubMed
MEDLINE
Embase
EBSCOhost
Cumulative Index to Nursing and Allied Health Literature (CINAHL)
International Pharmaceutical Abstracts (IPA)
ClinicalKey
Nexis Uni
BIOSIS Previews
Trip Database

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 Secondary resources (references)
• Indexing and abstracting are 2 common terms used when discussing
secondary resources
1. Indexing: providing bibliographic citation information (e.g., title, author,
citation of the article)
2. Abstracting: also includes a brief description (abstract) of the
information provided by the article

• There is a delay between article publication and indexing and

abstracting within secondary databases

• Various secondary electronic resources index and abstract information

from sources differently
o Should search various secondary resources for performing a
comprehensive search

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 Primary resources (references)

• Include clinical research studies and reports, both published and unpublished

• Types of publications considered primary references: controlled trials, cohort

studies, case series, and case reports

• Often provide the most in-depth information about a topic, and allow the
reader to analyze and critique the study methodology to determine if the
results and conclusions are valid

• Require strong literature evaluation skills and a longer time commitment to

review to accurately assess the value and application to health care

• May be available freely (e.g. open-access articles) or by paid subscription

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 Primary resources (references)

• Advantages of primary resources:

o Allows access to detailed information on specific interventions in various
patient populations
o Opportunity to evaluate the original literature and assess the validity and
applicability of study results

• Disadvantages of primary resources:

o Must develop strong literature evaluation skills to effectively use primary
literature
o Difficulty in performing a search to identify appropriate articles
o Time needed to evaluate the potentially large volume of available articles
o Difficult to determine which journals are most essential to pharmacy
practice

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 Primary resources (references)

Examples of top journals in medicine/pharmacy field:

New England Journal of Medicine (NEJM)

The Lancet
Journal of the American Medical Association (JAMA)
British Medical Journal (BMJ)
Annals of Internal Medicine
Nature Medicine
JAMA Internal Medicine

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 Primary resources (references)

Other selected examples of journal in medicine/pharmacy field:

Chest
Circulation
Clinical Infectious Diseases
Annals of Pharmacotherapy
Pharmacotherapy
PharmacoEconomics
American Journal of Health-System Pharmacy (AJHP)
Journal of The American Pharmacists Association (JAPhA)

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 Examples of useful resources for specific
categories of drug information
Pediatric pharmacotherapy
Compatibility, stability, and compounding
The Harriet Lane Handbook
(ASHP) Injectable Drug Information
Pediatric and Neonatal Dosage
Handbook King Guide to Parenteral Admixtures

Nelson Textbook of Pediatrics Trissel’s 2 Clinical Pharmaceutics Database

NeoFax USP-National Formulary (USP-NF)

BNF for Children Pediatric Injectable Drugs (The Teddy Bear Book)

Dietary and herbal supplement

Natural Medicines (NatMed)
Pregnancy and lactation
(MedicinesComplete) Dietary Supplements
Brigg’s Drugs in Pregnancy and Lactation
(MedicinesComplete) Herbal Medicines
LactMed
NIH’s Dietary Supplement Fact Sheets
NCCIH Health Information
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 The Harriet Lane Handbook

• Updated by residents, edited by chief

residents, and reviewed by expert faculty at
The Johns Hopkins Hospital every 3 years

• 23rd edition published in 2024

• Contents include:
o Emergency and Critical Care Management, Traumatic Injuries, Toxicology,
Adolescent Medicine, Analgesia and Procedural, Cardiology, Dermatology,
Development Behavior and Developmental Disability, Endocrinology, Fluids
and Electrolytes, Gastroenterology, Hematology, Immunology and Allergy,
Microbiology and Infectious Disease, Neonatology, Nephrology, Neurology,
Nutrition and Growth, Oncology, Palliative Care, Psychiatry, Pulmonology and
Sleep Medicine, Rheumatology

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 Trissel's™ 2 Clinical Pharmaceutics Database

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 Trissel's™ 2 Clinical Pharmaceutics Database

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 Pediatric Injectable Drugs
(The Teddy Bear Book)

• Published by ASHP

• 12th edition published in 2024

• Content covers:
o Medication error potential
o Infusion-related cautions
o Dosages and dose adjustment in organ dysfunction
o Additives and suitable diluents
o Maximum concentrations
o Preparation and delivery
o Bolus, intermittent, and continuous IV administration

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 Natural Medicines (NatMed)

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 Brigg's Drugs in Pregnancy and Lactation

• 12th edition published in 2021

• Lists more than 1400 of the most commonly

prescribed drugs taken during pregnancy and
lactation

• Each drug monograph includes:

o Pharmacologic class
o Pregnancy recommendation
o Breastfeeding recommendation
o Pregnancy summary
o Fetal risk summary (e.g. animal data,
placental transfer, human data)
o Breastfeeding summaries
o References

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 Brigg's Drugs in Pregnancy and Lactation

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 LactMed

• Each drug monograph

includes:
o Summary of Use
during Lactation
o Drug Levels
▪ Maternal levels
▪ Infant levels
o Effects in Breastfed
infants
o Effects on Lactation
and Breastmilk
o (References)

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 LactMed

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 Local Hong Kong medical resources
• Hong Kong MIMS
• DH Drug Office (e.g. Safety Alert, Medicines Recall, Newly Registered
Medicines, Letters to Healthcare Providers, Search Drug Database)
• DH Centre for Health Protection (e.g. Health Topics, Recommendations)
• HA Drug Formulary
• HA Drug Education Resources
• HK SHPHK Drug Education Resources Centre (DERC)

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 HK MIMS

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 HK DH Drug Office

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 HK DH Drug Office - Letters to Healthcare Providers

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 HK DH Drug Office – Search Drug Database

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 HK DH Centre for Health Protection

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 HK HA Drug Formulary

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 HK HA Drug Education Resources

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 HK SHPHK Drug Education Resources Centre

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 “Infodemic”

• With growing digitization – an expansion of social media and internet

use – information can spread more rapidly

• “Too much information including false or misleading information in digital

and physical environments during a disease outbreak”

• Possible consequences:
o Worsening of outbreaks when people are unsure about what they need
to do for protection
o Confusion and risk-taking behaviours that can harm health
o Mistrust in health authorities

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 “Infodemic”

• “Misinformation”
o “Spread of false information without the intent to mislead”

• “Disinformation”
o “Designed or spread with full knowledge of it being false (information has
been manipulated), as part of an intention to deceive”
o Possible motivations: e.g. economic gain, ideological, religious, political
or in support of a social agenda

• Both types can cause harm

• Key difference: knowledge and intention of the sender

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 Quality of health internet websites

• Evaluation of health information on the internet:

1. Who runs the site?

2. Who pays for the site?
3. What is the site’s purpose?
4. Is the health information high quality?
o How is the information selected and reviewed to make sure it's
accurate?
o Where does the information come from?
o Is the information up to date?
5. How does the website use your personal information?

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 Quality of mobile drug information app

• Smartphones have made obtaining health information online or via

mobile software applications (apps) much easier

• In 2019, a total of 81% of U.S. adults owned a smartphone, up from 35%

in 2011

• Criteria for evaluating mobile drug information app:

Usefulness Objectivity Design

Accuracy Timeliness Security
Authority Functionality Value

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 Patient education & Consumer health information

• 2 distinct ways patients receive information about medications

• Patient education:
o Delivers written or verbal drug information initiated by a health care
provider
o Pharmacists interact with individual patients to customize the
information to their specific situation
o Potential goals include changing patient behavior, improving adherence,
and ultimately improving patient health

• Consumer health information:

o Actively sought by the patient in response to their desire or need for
more information about their health or treatment
o Not individualized for a specific patient

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 Consumer health information

Examples of consumer health information platform:

Name Website
MedlinePlus https://medlineplus.gov/
Cleveland Clinic Health Library https://my.clevelandclinic.org/health
Mayo Clinic https://www.mayoclinic.org/
Drugs.com https://www.drugs.com/
WebMD® http://www.webmd.com
Centers for Disease Control and Prevention https://www.cdc.gov
Complementary and Integrative Health https://nccih.nih.gov
SafeMedication http://www.safemedication.com/

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 Off-label use

• Involves use of FDA-approved drug for an unapproved use

• Once the FDA approves a drug for marketing, a physician’s discretionary

use of that product is not restricted to the uses indicated on FDA-
regulated labelling

• Healthcare providers generally may prescribe the drug for an unapproved

use when they judge that it is medically appropriate for their patient

• 2 common reasons for off-label use of drugs:

1. No approved drug for treating a specific disease
2. Patient has tried all approved drugs without seeing any benefits

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 Off-label use

• Examples of clinical specialties in which significant portion of drug use is

off-label:
o Oncology, psychiatry, AIDS

• Examples of off-label uses of approved drugs:

oWhen a chemotherapy is approved to treat one type of cancer, but
healthcare providers use it to treat a different type of cancer
oWhen a drug is approved as a capsule for a specific indication, but it is
given instead in an oral solution
oWhen a drug is approved at a dose of 1 tablet every day, the physician
instructs the patient to take 2 tablets every day

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 Off-label use
• In providing responses to DI requests pertaining to off-label uses
(including usages of off-label dosages), it is prudent to provide complete
information

• When there is another drug on the market with an approved-label use for
the same indication that the off-label product is being considered, the
response to the DI request should mention that labeled alternative

• Off-label use of drugs has resulted in liability in the U.S.

o E.g. bevacizumab (Avastin® ), an oncology drug, used off-label to treat
macular degeneration, had caused blindness in some patients

• Off-label use is not necessarily experimental or investigational; thus,

informed consent is not necessary whenever an off-label use is proposed

Copyright © 2020. All Rights Reserved. Faculty of Medicine, The Chinese University of Hong Kong 47
 Adverse drug reaction

• WHO: “a response to a medicine which is noxious and unintended, and

which occurs at doses normally used in man”

• Classification of adverse drug reaction (ADR) can help health care

practitioners organize and present data, and facilitate monitoring of
ADR trends and potential causative agents
o Can be based on:
1. Severity
2. Mechanism
3. Probability / Causality

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 Adverse drug reaction

• Karch and Lasagna classification of ADR severity:

1. Minor: No antidote, therapy, or prolongation of hospitalization is required

2. Moderate: requires a change in drug therapy, specific treatment, or an

increase in hospitalization by at least 1 day

3. Severe: potentially life threatening, causing permanent damage or

requiring intensive medical care

4. Lethal: directly or indirectly contributes to the death of the patient

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 Adverse drug reaction

• Edwards and Arson classification of ADR mechanism:

A. Type A
o Most common, predictable from known pharmacology, dose-related
o Example: bleeding caused by anticoagulant

B. Type B
o Uncommon, unpredictable, not related to known pharmacology, non-dose-
related, potentially life-threatening
o Example: drug allergy

C. Type C
o Uncommon, dose-related and time-related (total dose over time)
o Example: osteonecrosis of the jaw with bisphosphonates

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 Adverse drug reaction

• Edwards and Arson classification of ADR mechanism:

D. Type D
o Uncommon, time-related (after longer use duration), usually also dose-
related
o Example: tardive dyskinesia caused by antipsychotic

E. Type E
o Uncommon, occurs soon after abrupt withdrawal of the drug
o Example: withdrawal symptoms caused by opioid termination

F. Type F
o Common, dose-related, can be caused by drug interactions
o Example: concurrent use of CYP3A4 substrate and CYP3A4 inducer

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 Adverse drug reaction
• Naranjo (Algorithm) ADR Probability Scale:

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 Adverse drug reaction
• Naranjo (Algorithm) ADR Probability Scale:

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 Adverse drug reaction

• Other examples of ADR probability/causality assessment tool:

o Bradford Hill criteria

o World Health Organization-Uppsala Monitoring Centre (WHO-UMC) scale

o Algorithm of Drug Causality for Epidermal Necrolysis (ALDEN)

▪ Specifically for assessing SJS and TEN

o Roussel Uclaf Causality Assessment Method (RUCAM)

▪ Specifically for assessing liver toxicity

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 Drug-induced teratogenicity
• Teratogen: agent that can cause abnormalities in the form or function of a
developing fetus

• The incidence of congenital malformation is ~3−6%

o <1% of all birth defects caused by medication exposure

• Adverse effects on the fetus depend on drug dosage, route of administration,

and stage of pregnancy when the exposure occurred

• Principles for drug use during pregnancy:

1. Select drugs that have been used safely for a long time
2. Prescribe doses at the lower end of the dosing range;
3. Eliminate nonessential medication and discouraging self-medication
4. Avoid medications known to be harmful

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 Drug-induced teratogenicity
Examples of drugs with potential adverse fetal effects

ACEIs, ARBs 5-alpha-reductase inhibitors

Ergotamine Dronedarone
Orlistat Leflunomide
Statins Raloxifene
Methotrexate Testosterone
Isotretinoin Misoprostol
Warfarin Ribavirin
Tetracycline Antineoplastic drugs

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 Australian categorisation system for
prescribing medicines in pregnancy
Pregnancy risk
Definition
categories
Category A Drugs which have been taken by a large number of pregnant women and
women of childbearing age without any proven increase in the frequency of
malformations or other direct or indirect harmful effects on the fetus having
been observed
Category B Drugs which have been taken by only a limited number of pregnant women
and women of childbearing age, without an increase in the frequency of
malformation or other direct or indirect harmful effects on the human fetus
having been observed

B1: Studies in animals have not shown evidence of an increased occurrence

of fetal damage
B2: Studies in animals are inadequate or may be lacking, but available data
show no evidence of an increased occurrence of fetal damage
B3: Studies in animals have shown evidence of an increased occurrence of
fetal damage, the significance of which is considered uncertain in humans

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 Australian categorisation system for
prescribing medicines in pregnancy

Pregnancy risk
Definition
categories
Category C Drugs which, owing to their pharmacological effects, have caused or
may be suspected of causing, harmful effects on the human fetus or
neonate without causing malformations. These effects may be
reversible. Accompanying texts should be consulted for further details.
Category D Drugs which have caused, are suspected to have caused or may be
expected to cause, an increased incidence of human fetal
malformations or irreversible damage. These drugs may also have
adverse pharmacological effects. Accompanying texts should be
consulted for further details.
Category X Drugs which have such a high risk of causing permanent damage to the
fetus that they should not be used in pregnancy or when there is a
possibility of pregnancy.

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 Pregnancy and Breastfeeding Medicines Guide (PBMG)

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 Drug interaction
• A drug interaction can involve the interaction of a drug with a nutrient,
chemical, food, herbal, disease, or laboratory test

• A “drug-drug interaction (DDI)” is a clinically meaningful alteration in the

exposure and/or response to a drug (object drug) that has occurred as a
result of the coadministration of another drug (precipitant drug)

• A “clinically relevant DDI” is a DDI associated with either toxicity or loss of

efficacy that warrants the attention of healthcare professionals

• Interactions between drugs in vitro (e.g. precipitation when mixed in

solutions for IV administration) are usually classified as drug
incompatibilities, not drug interactions

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 Categories of drug interactions

Pharmacodynamic Pharmacokinetic

Absorption
Additive effect

Distribution
Antagonistic effect
Metabolism

Synergistic effect
Excretion

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 Pharmacodynamic drug interactions

• Pharmacodynamic interaction refers to a change in the

pharmacodynamics of one drug caused by the interacting drug
o i.e. the response of one drug is modified by the presence of another one
without alterations in pharmacokinetics

• Mechanisms:

The effect of 2 drugs given together is equal to the sum of the

Additive
responses to the same doses given separately (1 + 1 = 2)
The effect of 2 drugs given together is less than the sum of the
Antagonistic
responses to the same doses given separately (1 + 1 < 2)
The effect of 2 drugs given together is greater than the sum of
Synergistic
the responses to the same doses given separately (1 + 1 > 2)

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 Pharmacodynamic drug interactions

Examples of the additive or synergistic effects

Interacting agent 1 Interacting agent 2 Results
Anticoagulant Antiplatelet Increased bleeding potential
Sildenafil Nitrate Increased hypotensive effect
Sulfamethoxazole Trimethoprim Enhanced antibacterial effect

Examples of the antagonistic effects

Interacting Interacting
Results
agent 1 agent 2
Flumazenil reverses the
Benzodiazepine Flumazenil
sedative effect of a benzodiazepine
Salbutamol Propranolol Reduced bronchodilatory effect of salbutamol

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 Pharmacokinetic drug interactions

Absorption
Altered gastric pH
Distribution
Complexation (chelation/adsorption)
of drugs Displacement of
highly protein-bound drugs
Altered gastrointestinal motility
Altered p-glycoprotein (P-gp) activity

Excretion
Metabolism Change in renal tubular
reabsorption of drug
CYP enzymes
Change in renal tubular
secretion of drug

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 Exercise 1:
What type of resource does the following belong to?

1. Journal of Clinical Pharmacy and Therapeutics

2. Product’s prescribing information (package insert)
3. PsycINFO
4. U.S. Food and Drug Administration (FDA) website
5. NEJM Journal Watch
6. Cochrane Library
7. Drugs.com
8. Medscape
9. Google Scholar
10. Harrison’s Principles of Internal Medicine
11. British National Formulary (BNF)
12. Electronic medicines compendium (EMC)

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 Exercise 2:
Name a drug information reference that you would use
for answering the following drug information requests.

1. A doctor asks: “Is gentamicin eye drop safe for pregnancy?”

2. A doctor asks: “How to manage a patient who has paracetamol acute
poisoning?”
3. A doctor asks: “What is the pharmacokinetic information of Augmentin for
a 7-year-old patient?”
4. A nurse asks: “Are phenobarbital and phenobarbitone the same drug”
5. A nurse asks: “If a patient is bedbound with dysphagia, can I crush
Fosamax tablet and serve?”
6. A nurse asks: “How long can cyanocobalamin injection be stable?”
7. A nurse asks: “Can enoxaparin be administered via IM but not SC route?”

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 Exercise 2 (cont’d):
Name a drug information reference that you would use
for answering the following drug information requests.

8. A nurse asks: “Can I give Nexium 0.8 mg/mL and Lactated Ringer’s
(LR) together via Y-site for IV infusion?”
9. A patient asks what strength and dosage form of semaglutide are
available in HK now
10. A Portuguese patient who is unable to speak English and Chinese
requests the drug Information of Azarga® eye drop in Portuguese
11. A female patient asks whether she can use dextromethorphan as cough
suppressant during lactation
12. A female patient is planning to have a child, and asks whether the use
of ibuprofen can impair her fertility
13. A client would like to know the beneficial effect and side effect of
melatonin when used for insomnia

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