Lecture 20: Misuse of OTC Drugs & Poisonings

Question 1

FDA definition of abuse

Answer 1

“the intentional, non-therapeutic use of a drug, even once, for its desirable or physiological effects”.

Question 2

FDA definition of misuse

Answer 2

“the intentional use, for therapeutic purposes, of a

drug by an individual in a way other than prescribed by a health care provider

Question 3

Misuse→

Answer 3

intent to treat therapeutic need

Question 4

Abuse →

Answer 4

non-therapeutic use

Question 5

Common Reasons for Misuse/Abuse of OTC Drugs

Answer 5

● Weight loss
● Suicide
● Euphoria
● Stimulant effects/wakefulness

Question 6

Dextromethorphan

Answer 6

Used/abused for euphoria
○ ‘Robotripping’
Normal dose: up to 120mg, given in divided doses

Question 7

Dextromethorphan Abuse dose

Answer 7

○ 100 -120mg per dose - restlessness and euphoria
○ >200mg - auditory/visual perception changes
○ >1000mg - complete dissociation and hallucinations

Question 8

Dextromethorphan Mechanism of abuse:

Answer 8

Blocks NMDA receptor

○ Similar to abuse of PCP, ketamine

Question 9

Dextromethorphan Risks

Answer 9

○ Serotonin syndrome
○ QT prolongation
○ CNS depression
○ Death

Question 10

Dextromethorphan Restrictions:

Answer 10

○ RX only in some states

○ Must be 18 years old to purchase in some states

Question 11

Loperamide

Answer 11

● Used/abused for euphoria (or to avoid/treat opioid withdrawal)
Normal dose: 8mg daily (self-care) up to 16mg daily (RX)

Question 12

Loperamide Abuse Dose

Answer 12

Abuse dose: 70-100mg daily (reports of up to 1200mg daily)

Question 13

Loperamide Mechanism of Abuse

Answer 13

○ Weak opioid receptor agonist
○ Requires very high doses
■ Combine with CYP3A4 and CYP2C8 to increase metabolism
■ Combine with pgp-inhibitor to enhance absorption in CNS

Question 14

Loperamide Risks

Answer 14

○ Cardiac arrest
○ QT prolongation
○ Syncope
○ Cardiac arrhythmias

Question 15

Loperamide Restrictions

Answer 15

○ September 2019: FDA approved a change limiting packages to a maximum 48mg

Question 16

First Generation Antihistamines

Answer 16

● Used/abused for euphoria, high energy, positive mood

● Normal dose: 25-50mg every 4 to 6 hours

Question 17

First Generation Antihistamines Abused Dose

Answer 17

Abuse dose: 3-5x usual dose

75-150mg or 125-250mg every 4-6 hrs

Question 18

First Generation Antihistamines Mechanism of Abuse

Answer 18

○ Increase dopamine transmission

Question 19

First Generation Antihistamines Risks

Answer 19

○ Psychosis
○ Changes in heart rhythm
○ Urinary retention
○ CNS depression

Question 20

First Generation Antihistamines Limitations

Answer 20

None

Question 21

Tetrahydrozoline

Answer 21

Used/abused for potential to impair another individual
○ CNS depression, muscle weakness, decreased heart rate, and decreased blood pressure
○ Onset in 15-30 minutes and effects diminish within 24 hours
○ Clear and odorless
● Normal dose: 1-2 drops applied to eyes/nose

Question 22

Tetrahydrozoline Abused Dose

Answer 22

Abuse dose: Ingested orally

Question 23

Tetrahydrozoline Mechanism of Abuse

Answer 23

○ Lipophilic, so low systemic absorption/ADRs if absorbed after nasal/ocular administration
○ Crosses BBB after ingestion to stimulate alpha-2 receptors and agonize imidazoline-1 receptor

Question 24

Tetrahydrozoline Restrictions

Answer 24

None

Question 25

Pseudoephedrine/Ephedrine

Answer 25

Used/abused for stimulant properties
○ Increases heart rate and BP, elevates mood, appetite suppression
● Normal dose: 120mg daily ephedrine

Question 26

Pseudoephedrine/Ephedrine Abused Dose

Answer 26

1450mg daily ephedrine

Question 27

Pseudoephedrine/Ephedrine Mechanism of Abuse

Answer 27

○ Sympathomimetics

○ Structurally similar to norepinephrine

Question 28

Pseudoephedrine/Ephedrine other notes

Answer 28

● ALSO - used to make methamphetamine
● 2005 Combat Methamphetamine
Epidemic Act
○ Led to restrictions on pseudoephedrine
purchases (daily and monthly)

Question 29

Laxatives

Answer 29

Used/abused for weight loss
○ Rare in typical population (0.7-5.5%)
○ High rate in population with anorexia/bulimia diagnosis (3-70%)
○ Stimulants are most commonly abused class

Question 30

Laxatives

Answer 30

○ Used to stimulate bowel movements (purging)

Question 31

Laxatives

Answer 31

○ Electrolyte imbalance

○ Nutritional deficiencies

Question 32

Laxatives

Answer 32

○ UK just passed a law limiting sales
■ Retail outlets can sell to 18 and older
■ Pharmacists can sell for use in 12 and
older
■ Additional warnings about abuse
potential added to labelling

Question 33

Pharmacist Prevention Tactics

Answer 33

● Keep drugs out of sight
● Question purchase of the medication
● Refusal to sell
● Referral to physician
● Counseling about abuse/misuse potential

Question 34

Barriers to Pharmacist Prevention

Answer 34

● Challenges in identifying drug related problems
○ Lack of record-keeping with OTC medications
● Lack of widespread tracking or tracking between pharmacies
○ Pseudoephedrine is the exception with the 2005 Combat Methamphetamine Epidemic Act
● Other pharmacist tasks
○ How can technicians help?

Question 35

The Pharmacist’s Role in Drugs of Misuse

Answer 35

● Drug take-back programs
○ Partner with local sheriff’s office
○ Sell drug disposal products
○ Advertise for local events
● Educate parents and grandparents
● Health literacy

Question 36

Behind the Counter?

Answer 36

● Drugs that are available only after consultation with a pharmacist
○ No prescription required, but cannot be purchased OTC
● Has been reviewed by the FDA in the past → not currently a formal category
in the U.S.
● Would allow a pharmacist to assess safety, efficacy, appropriateness
● Requires more training for pharmacists and technicians in order to offer the
required assessment
● Proposed medications: codeine products, pseudoephedrine,
diphenhydramine, statins, insulin

Question 37

Poisoning Epidemiology

Answer 37

● Poisonings are the #1 cause of injury death in the United States and a
significant cause of morbidity
● Poisoning tends to be accidental in children
● Poisoning may be accidental or intentional in adults
○ Suicide attempt
○ Substance abuse
○ Medication misuse
● Exposure:
○ Ingestion
○ Topical
○ Inhaled
○ Bites/envenomation

Question 38

Acetaminophen: One of the leading causes of poisoning from OTC medications

Answer 38

○ Misunderstandings/confusion about use/misuse
○ Accidental overdose from using multiple APAP containing products
○ Intentional misuse - easy access

Question 39

Acetaminophen: ● Initiatives to improve patient understanding

Answer 39

○ Knowyourdose.org
○ Convert children/infant doses to same concentration to prevent math errors
○ Highlight APAP ingredient on product labels

Question 40

Poison Control Centers

Answer 40

● 24 hours sources of:
○ Poison information
○ Clinical toxicology consultation
○ Poison prevention education
● Staffed by pharmacists, nurses, physicians,
PAs who have additional tox training
● Available for public or healthcare provider
consultation
● Contact for assessment/treatment of
poisonings OR for educational material

Question 41

Poison Control Number

Answer 41

1-800-222-1222

Question 42

Poisoning Stats

Answer 42

● 47.7% of reported cases are in children <6
● Common non-RX products:
○ Analgesics
○ Cough/cold
○ Topical preparations
○ Vitamins
○ Antihistamines
● 70% of calls to Poison Control Centers can be managed at home

Question 43

Poison Prevention Packaging Act (1970)

Answer 43

● Purpose: Protect children under 5 from accidental poisoning and death
● Legislated requirement for child-resistant closures (CRC) on possible poisons
● This has reduced the fatalities due to both RX and non-RX exposure

Question 44

PPPA - OTC Medications

Answer 44

● Mouthwash containing ≥3g ethanol
● Aspirin
● Prescription and controlled medications

Question 45

PPPA - OTC Medications Products containing:

Answer 45

○ ≥1g acetaminophen
○ ≥1g ibuprofen
○ ≥66mg diphenhydramine base
○ ≥0.045mg loperamide
○ ≥250mg elemental iron
○ ≥250mg naproxen
○ ≥14mg minoxidil

Question 46

Child Resistant Packaging

Answer 46

● “Designed or constructed to be significantly difficult for children under 5 to
open or obtain a harmful amount of the contents within a reasonable amount
of time”
● 80% of the children tested must not be able to open the package within 10
minutes
● Also tested in adults to make sure it can be opened: 90% of adults must be
able to open within 5 minutes

Question 47

Exemptions to Child Resistant Packaging

Answer 47

● OTC brands may package one size with non-child resistant packaging
○ Must offer other sizes that are child resistant
● OTC exempted products must label:
○ “This package for households without young children”
○ “Package not child resistant”
● Individuals may request that prescriptions are not placed in child resistant
packaging

Question 48

Clinical Presentation of Poisoning

Answer 48

● Presentation may vary depending on the drug
● May mimic side effect profile with normal use
○ Ibuprofen → nausea, vomiting, abdominal pain
○ Diphenhydramine → sedation, stimulation, tachycardia, hypertension, dry mouth, dilated pupils
● Others may have more widespread organ effects
○ Aspirin → GI, CNS, metabolic, CV, pulmonary, hematologic
● Signs/symptoms may be delayed
○ ER or enteric coated products may have delayed absorption
○ Delayed gastric emptying or slowed GI motility (diphenhydramine)
○ Metabolism to toxic metabolites (APAP)

Question 49

Treatment of Poisoning

Answer 49

First step: Determine if the patient has symptoms and if the exposure puts the
patient at risk of toxicity
● Self-care treatment is ONLY appropriate if:
○ Exposure was unintentional
○ Toxicity risk is assessed to be minor

Question 50

Exclusions for Self-Care Treatment

Answer 50

● Intentional exposure/substance abuse
● Expected suicide or homicide
● Inadvertent exposure with moderate/severe toxicity risk
● Exhibiting life-threatening clinical effects (coma, convulsion, syncope)
○ Call 911 and transport to ER
● Suspected child abuse or elder abuse
● Debilitated or advanced age
● Absent or poor gag reflex
● CNS depression

Question 51

What can a hospital do?

Answer 51

● Supportive care
○ Keep airway open
○ Fluids
● Prevent absorption
● Increase elimination
● Utilize antidotes

Question 52

Nonpharmacologic Management

Inhalation exposure

Answer 52

remove from source to fresh air

Question 53

Nonpharmacologic Management

Skin/mucosal exposure -

Answer 53

irrigation
○ Wash skin with soap and water (pay attention to nail beds and hair)
○ Use water/saline solution to irrigate eyes

Question 54

Nonpharmacologic Management

Ingestion

Answer 54

○ Administering large amounts of fluids → may cause spontaneous vomiting
○ Some drugs may require fluid dosing
■ Bisphosphonates + esophageal irritation
■ Ibuprofen + renal injury
○ Avoid stimulating the gag reflex manually

Question 55

Pharmacologic Options: Activated charcoal

Answer 55

○ Adsorbent

○ Controversial use

Question 56

Pharmacologic Options: Ipecac syrup

Answer 56

Ipecac syrup
○ Emetic
○ Does not improve outcomes → avoid
○ Also not easily purchased

Question 57

Activated Charcoal Characteristics

Answer 57

● Tasteless, gritty, fine, black, insoluble powder
● Large surface area so it’s a highly effective adsorbent
● As the ratio of activated charcoal to toxin increases, the proportion of bound
toxin increases

Question 58

Activated Charcoal: Poor adsorbent of:

Answer 58

○ Lithium, potassium (highly ionized)
○ Alcohols
○ Hydrocarbons
○ Mineral acids
○ Heavy metals
○ Cyanide

● Food in GI tract may effect efficacy

Question 59

Activated Charcoal

Answer 59

● Approved by the FDA for use as emergency antidote for ingested poison
● Home use should only include ONE DOSE
● Usual dose: 1g/kg

Question 60

Activated Charcoal

Available in different formulations

Answer 60

○ Premixed with water
○ Premixed with water + carboxymethylcellulose
○ Premixed with sorbitol (decreases GI transit time)

Question 61

Activated Charcoal

Contraindications:

Answer 61

○ GI tract not anatomically or functionally intact
○ Bariatric surgery may require dose adjustments
○ High risk of aspiration
○ If the toxin does not adsorb to charcoal

Question 62

Activated Charcoal Patient Education

Answer 62

● Products should be shaken vigorously prior to administration
● Some products may have flavoring agents to improve palatability
● Common ADRs:
○ Vomiting (12-20%)
○ Black stool

Question 63

Activated Charcoal

Considerations

Answer 63

● Works best if administered quickly (works best within one hour)
● It is available as a non-RX drug
● Not typically found in most homes
● Not routinely recommended by a poison center
● Conclusion: it is relatively safe, but it is probably not something that people need or should be recommended to keep around their house due to its controversial place in practice and possibly limited efficacy (especially in selfcare situations)