[DISPENSING] Therapeutic Incompatibilities & Drug Interactions Part 1

a. Drug interaction

Situation in which the pharmacologic effects of one drug are altered by prior or concurrent administration of another substance.

a. Drug interaction

b. Therapeutic incompatibility

c. Physicochemical incompatibility

d. Adverse drug reaction

c. Therapeutic incompatibility

Results in potentiation of therapeutic effects

a. Physical incompatibility
b. Chemical incompatibility
c. Therapeutic incompatibility
d. Biological incompatibility

c. Therapeutic incompatibility

[THERAPEUTIC INCOMPATIBILITIES]

Results in destruction of effectiveness of one or more ingredients

a. Physical incompatibility
b. Chemical incompatibility
c. Therapeutic incompatibility
d. Biological incompatibility

c. Therapeutic incompatibility

[THERAPEUTIC INCOMPATIBILITIES]
Results in occurrence of toxic manifestations in patients.

a. Physical incompatibility
b. Chemical incompatibility
c. Therapeutic incompatibility
d. Biological incompatibility

a. Object Drug

[THERAPEUTIC INCOMPATIBILITIES]
Affected by the interaction

a. Object Drug

b. Precipitant Drug

b. Precipitant Drug

[THERAPEUTIC INCOMPATIBILITIES]
Caused the interaction

a. Object Drug

b. Precipitant Drug

b. Tetracycline

[THERAPEUTIC INCOMPATIBILITIES]
In the example Tetracycline + Antacids, which is the object drug?

a. Antacids
b. Tetracycline
c. Both
d. Neither

b. Antacids

[THERAPEUTIC INCOMPATIBILITIES]
In the example Tetracycline + Antacids, which is the precipitant drug?

a. Tetracycline

b. Antacids

c. Both

d. Neither

c. Chelation reaction

[THERAPEUTIC INCOMPATIBILITIES]

The interaction between Tetracycline and Antacids results in which type of reaction?

a. Oxidation

b. Hydrolysis

c. Chelation reaction

d. Racemization

c. Chelate complex (macromolecule)

[THERAPEUTIC INCOMPATIBILITIES]

Tetracycline will bind to the antacid forming a ______

a. Oxidation

b. Hydrolysis

c. Chelate complex (macromolecule)

d. Racemization

b. Inactivation of tetracycline = ↓ absorption ↓ effect ↓ BA

[THERAPEUTIC INCOMPATIBILITIES]

Chelation between Tetracycline and Antacids results in:

a. Increased absorption

b. Inactivation of tetracycline = ↓ absorption ↓ effect ↓ BA

c. Increased potency

d. No change in effect

• Polypharmacy

• Multiple prescribers secondary to polypharmacy

• Multiple pharmacological effects of drugs (e.g. off label effects)

• Multiple diseases/predisposing illness

• Poor patient compliance

• Age of patient

• Drug related factors

Risk Factors Contributing to Drug Interactions

a. Established

[CLASSIFICATION OF DRUG INTERACTIONS]

A drug interaction supported by well-proven clinical studies

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikel

b. Probable

[CLASSIFICATION OF DRUG INTERACTIONS]

A drug interaction that is very likely but might not be proven clinically

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikel

c. Suspected

[CLASSIFICATION OF DRUG INTERACTIONS]

A drug interaction that might occur

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

c. Suspected

[CLASSIFICATION OF DRUG INTERACTIONS]

Some data might be available

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

d. Possible

[CLASSIFICATION OF DRUG INTERACTIONS]

A drug interaction that could occur

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

d. Possible

[CLASSIFICATION OF DRUG INTERACTIONS]

Limited data are available

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

e. Unlikely

[CLASSIFICATION OF DRUG INTERACTIONS]

A drug interaction that is doubtful

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

e. Unlikely

[CLASSIFICATION OF DRUG INTERACTIONS]

No good evidence of an altered clinical effect is available

a. Established

b. Probable

c. Suspected

d. Possible

e. Unlikely

a. True

[DRUG-HERB INTERACTIONS]

St. John's wort decreases blood levels of Digoxin, reducing its efficacy.

a. True

b. False

a. True

[DRUG-HERB INTERACTIONS]

St. John's wort is an enzyme inducer that decreases Digoxin blood levels.

a. True

b. False

b. Additive anticoagulation and bleeding

[DRUG-HERB INTERACTIONS]

Garlic, Ginkgo, and Ginger interact with Warfarin or Heparin to cause _____

a. Decreased anticoagulation

b. Additive anticoagulation and bleeding

c. Increased metabolism of Warfarin

d. No effect

a. Decreased warfarin activity and increased coagulation.

[DRUG-HERB INTERACTIONS]

Warfarin + Asian ginseng results in:

a. Decreased warfarin activity and increased coagulation.

b. Increased warfarin activity and decreased coagulation.

b. Double sedation (additive effect)

[DRUG-HERB INTERACTIONS]

Sedative + Valerian results in:

a. Antagonism

b. Double sedation (additive effect)

c. No interaction

d. Decreased sedation

a. Increase hypoglycemic effect

[DRUG-HERB INTERACTIONS]

Hypoglycemic agents + Ginseng results in:

a. Increase hypoglycemic effect

b. Decrease hypoglycemic effect

b. Poorly managed hypertension

[DRUG-HERB INTERACTIONS]

Anti-HTN agents + Licorice result in:

a. Hypotension
b. Poorly managed hypertension
c. Additive antihypertensive effect
d. No interaction

b. Ginseng

[HERBAL PREPARATIONS]

Adaptogen.

a. Echinacea
b. Ginseng
c. Ginkgo
d. Valerian

c. Echinacea

[HERBAL PREPARATIONS]

Used for cold symptoms.

a. Ginseng
b. Milk Thistle
c. Echinacea
d. St. John's Wort

b. Ginkgo

[HERBAL PREPARATIONS]

Memory aid that increases brain circulation.

a. Valerian
b. Ginkgo
c. Saw Palmetto
d. Feverfew

c. Milk Thistle

[HERBAL PREPARATIONS]

Hepatoprotection.

a. St. John's Wort
b. Echinacea
c. Milk Thistle
d. Ginseng

d. St. John's Wort

[HERBAL PREPARATIONS]

Uplifts mood (Hypericin)

a. Valerian
b. Saw Palmetto
c. Feverfew
d. St. John's Wort

d. St. John's Wort

[HERBAL PREPARATIONS]

Contains hypericin

a. Valerian
b. Saw Palmetto
c. Feverfew
d. St. John's Wort

b. Valerian

[HERBAL PREPARATIONS]

Sleeping aid.

a. Ginkgo
b. Valerian
c. Ginseng
d. Echinacea

c. Saw Palmetto

[HERBAL PREPARATIONS]

Used for enlarged prostate.

a. Feverfew
b. Milk Thistle
c. Saw Palmetto
d. St. John's Wort

c. Feverfew

[HERBAL PREPARATIONS]

Used for migraines/fever.

a. Ginkgo
b. Valerian
c. Feverfew
d. Ginseng

d. Rifampicin + Urinalysis

Causes masking of color.

a. Ascorbic Acid + Glucose Test

b. Allopurinol + Cholesterol Level

c. Vitamin B7 + Troponin-based Assays

d. Rifampicin + Urinalysis

b. Rifampicin

[DRUGS THAT CHANGE URINE COLOR]

Drug that turns urine orange.

a. Chloroquine
b. Rifampicin
c. Metronidazole
d. Riboflavin

c. Chloroquine

[DRUGS THAT CHANGE URINE COLOR]

Drug that turns urine brown.

a. Rifampicin
b. Vitamin B2
c. Chloroquine
d. Metronidazole

c. Vitamin B2 / Riboflavin

[DRUGS THAT CHANGE URINE COLOR]

Drug that turns urine intense yellow.

a. Rifampicin
b. Chloroquine
c. Vitamin B2 / Riboflavin
d. Metronidazole

d. Metronidazole

[DRUGS THAT CHANGE URINE COLOR]

Drug that turns urine gray.

a. Rifampicin
b. Chloroquine
c. Vitamin B2
d. Metronidazole

a. Ascorbic Acid + Glucose Test

[DRUG-LAB TEST INTERACTIONS]

Causes false increase of glucose

a. Ascorbic Acid + Glucose Test

b. Allopurinol + Cholesterol Level

c. Vitamin B7 + Troponin-based Assays

b. Allopurinol + Cholesterol Level

[DRUG-LAB TEST INTERACTIONS]

Causes false increase of cholesterol

a. Ascorbic Acid + Glucose Test

b. Allopurinol + Cholesterol Level

c. Vitamin B7 + Troponin-based Assays

c. Vitamin B7 + Troponin-based Assays

[DRUG-LAB TEST INTERACTIONS]

Causes false low results

a. Ascorbic Acid + Glucose Test

b. Allopurinol + Cholesterol Level

c. Vitamin B7 + Troponin-based Assays

b. Decreased absorption

[DRUG-FOOD INTERACTIONS]

Quinolone / Tetracycline + Ca-rich foods results in:

a. Increased absorption
b. Decreased absorption

b. Decreased warfarin activity

[DRUG-FOOD INTERACTIONS]

Warfarin + green leafy vegetables (Vitamin K) results in:

a. Increase warfarin activity
b. Decreased warfarin activity

a. Antagonism

[DRUG-FOOD INTERACTIONS]

Warfarin + green leafy vegetables (Vitamin K) results in:

a. Antagonism
b. Agonism

b. Decreased anticoagulant effect

[DRUG-FOOD INTERACTIONS]

Warfarin + green leafy vegetables (Vitamin K) results in:

a. Increased anticoagulant effect
b. Decreased anticoagulant effect

a. Increased risk of MI and stroke

[DRUG-FOOD INTERACTIONS]

Warfarin + green leafy vegetables (Vitamin K) results in:

a. Increased risk of MI and stroke
b. Decreased risk of MI and stroke

b. Decreased metabolism

[DRUG-FOOD INTERACTIONS]

Drug + grapefruit results in:

a. Increased metabolism
b. Decreased metabolism

a. Disulfiram-like reaction (idiosyncratic reaction, Type B ADR)

[DRUG-FOOD INTERACTIONS]

Metronidazole + alcohol results in a _____

a. Disulfiram-like reaction (idiosyncratic reaction, Type B ADR)

b. Hypertensive crisis

c. Additive sedation

d. Increased metabolism of metronidazole

a. Hypertensive crisis

[DRUG-FOOD INTERACTIONS]

MAOIs + tyramine-rich food results in_______

a. Hypertensive crisis
b. Hypotensive crisis

a. Poorly managed hypertension

[DRUG-FOOD INTERACTIONS]

Anti-HTN agents + licorice results in:

a. Poorly managed hypertension

b. Greatly managed hypertension

a. True

[DRUG-FOOD INTERACTIONS]

Spironolactone + K-rich food results in ______

a. Hyperkalemia

b. Hypokalemia

a. Increased absorption

[DRUG-FOOD INTERACTIONS]

Griseofulvin + fatty food results in:

a. Increased absorption

b. Decreased absorption

b. Decreased bioavailability (BA)

[DRUG-FOOD INTERACTIONS]

Bisphosphonate + food / mineral water results in:

a. Increased bioavailability (BA)

b. Decreased bioavailability (BA)

a. Additive lipid-lowering effect

[DRUG-FOOD INTERACTIONS]

Statins + red yeast rice results in:

a. Additive lipid-lowering effect

b. Synergistic lipid-lowering effect

a. Additive side effect

Statins + red yeast rice results in:

a. Additive side effect

b. Synergistic side effect

a. Higher risk than benefit

[DRUG-FOOD INTERACTIONS]

Statins + red yeast rice results in a:

a. Higher risk than benefit
b. Higher benefit than risk

a. Increased absorption

[DRUG-FOOD INTERACTIONS]

Antihistamines + apple/orange juice results in:

a. Increased absorption
b. Decreased absorption

a. Idiosyncratic reaction

Antihistamines + apple/orange juice results in:

a. Idiosyncratic reaction
b. Increased absorption
c. Additive sedation
d. Hypertensive crisis

b. Decreased absorption

[DRUG-FOOD INTERACTIONS]

Digoxin + oatmeal results in _____
a. Increased absorption
b. Decreased absorption

a. Pharmacologic Antagonism

[PHARMACODYNAMIC INTERACTIONS]

• Antagonist interacts with the same pathway

• Produces opposing effect

a. Pharmacologic Antagonism

b. Physiologic Antagonism

c. Chemical Antagonism

b. Physiologic Antagonism

[PHARMACODYNAMIC INTERACTIONS]

• Interacts with a different pathway

• Produces opposing effect

a. Pharmacologic Antagonism

b. Physiologic Antagonism

c. Chemical Antagonism

c. Both a and b

• Competitive

• Non-competitive

Types of Pharmacologic Antagonism include:

a. Competetive

b. Non-competitive

c. Both a and b

c. Chemical Antagonism

[PHARMACODYNAMIC INTERACTIONS]

Directly interacts or antagonizes the object drug

a. Pharmacologic Antagonism

b. Physiologic Antagonism

c. Chemical Antagonism

c. Chemical Antagonism

[PHARMACODYNAMIC INTERACTIONS]

Reduces or inhibits the action of the object drug

a. Pharmacologic Antagonism

b. Physiologic Antagonism

c. Chemical Antagonism

a. Additive

[PHARMACODYNAMIC INTERACTIONS]

Sum of the effect of each drug used individually is higher than the effect of drug alone (1 + 1 = 2).

a. Additive

b. Synergistic

c. Potentiation

d. Antagonistic

b. Synergistic

[PHARMACODYNAMIC INTERACTIONS]

Enhanced efficacy of the combination (1 + 1 = 3).

a. Additive

b. Synergistic

c. Potentiation

d. Antagonistic

c. Potentiation

[PHARMACODYNAMIC INTERACTIONS]

One drug has no effect on its own but increases the effect of the other 1 + 0 = 2 or 1 + 0 > 2).

a. Additive

b. Synergistic

c. Potentiation

d. Antagonistic

d. Antagonistic

[PHARMACODYNAMIC INTERACTIONS]

Effect of one drug is decreased or suppressed by another drug (1 + 1 = 0)

a. Additive

b. Synergistic

c. Potentiation

d. Antagonistic

d. Antagonistic

[PHARMACODYNAMIC INTERACTIONS]

Non-beneficial (1 + 1 = 0)

a. Additive

b. Synergistic

c. Potentiation

d. Antagonistic

• Alcohol + CNS Depressants, Barbs, Antihistamines, Chloral hydrate

• Aminoglycosides + Loop diuretics

• Aminoglycoside + NMB

• Diuretics + NMB

• Diuretics + Digitalis

• BZDs + Antihistamine

• B-blockers + CCBs

• Antiddepressants + Azithromycin

[PHARMACODYNAMIC INTERACTIONS]

Example of Drug with Additive effects [8]

a. Additive sedative effect

[PHARMACODYNAMIC INTERACTIONS]

Alcohol + CNS Depressants, Barbs, Antihistamines, Chloral hydrate result in:

a. Additive sedative effect

b. Synergistic sedative effect

c. Antagonistic sedative effect

a. Ototoxicity

[PHARMACODYNAMIC INTERACTIONS]

Aminoglycosides + Loop diuretics → ______

a. Ototoxicity

b. Nephrotoxicity

c. Hepatoxicicty

a. NM blockade

[PHARMACODYNAMIC INTERACTIONS]

Aminoglycosides + Neuromuscular blockers (NMB) results in:

a. NM blockade
b. Increased renal clearance
c. Additive sedation
d. Hypotension

b. Variable effect

[PHARMACODYNAMIC INTERACTIONS]

Diuretics + Neuromuscular blockers (NMB) results in:

a. Same effect
b. Variable effect

b. Digitalis toxicity

[PHARMACODYNAMIC INTERACTIONS]

Diuretics + Digitalis results in:

a. Increased diuresis
b. Digitalis toxicity
c. Hypokalemia only
d. Additive sedation

b. Double sedation

[PHARMACODYNAMIC INTERACTIONS]

Benzodiazepines (BZDs) + Antihistamine result in:

a. Antagonism
b. Double sedation
c. Serotonin syndrome
d. Hypertensive crisis

c. Heart block

[PHARMACODYNAMIC INTERACTIONS]

Beta-blockers + Calcium channel blockers (CCBs) result in:

a. Hypertension
b. Tachycardia
c. Heart block
d. Additive sedation

a. QT prolongation

[PHARMACODYNAMIC INTERACTIONS]

Antidepressants + Azithromycin result in:

a. QT prolongation
b. Serotonin syndrome
c. Hypertensive crisis
d. Additive sedation

• Trimethoprim + Sulfamethoxazole → Cotrimoxazole (Bactrim®)

• Ezetimibe + Simvastatin → Vytorin®

• Amlodipine + Valsartan → Exforge®

• Antiretroviral therapy

[PHARMACODYNAMIC INTERACTIONS]

Example of Drug with Synergistic effects [4]

• Amoxicillin + Clavulanic acid → Augmentin®, Amoclav®

• Ticarcillin + Clavulanic acid → Timentin®

• Ampicillin + Sulbactam → Unasyn®

• Piperacillin + Tazobactam → Piptaz®, Zosyn®

• Imipenem + Cilastatin → Primaxin®

• Levodopa + Carbidopa → Sinemet®

[PHARMACODYNAMIC INTERACTIONS]

Example of Drug with Pontentiation effects [6]

• Drugs having opposed pharmacologic effects

• Drugs having similar pharmacologic effects

• Alteration of electrolyte concentration

• Interaction at receptor sites

[PHARMACODYNAMIC INTERACTIONS]

Type of Drugs that causes ANTAGONISM [4]

c. Both a and b

• Diuretics + anti-diabetics

• Diuretics + anti-hyperuricemic agents

[PHARMACODYNAMIC INTERACTIONS]

Drugs having opposed pharmacologic effects include:

a. Diuretics + anti-diabetics

b. Diuretics + anti-hyperuricemic agents

c. Both a and b

• Colchicine

• Allopurinol

Example of Anti-hyperuricemic agents [2]

• CNS depressants

  • Anti-psychotics

  • TCAs

  • Opioid analgesics

  • Most antihistamines

  • Sedative-Hypnotics (S/H) and Alcohol (OH) → causes additive CNS depressant effects.

• Drugs with anticholinergic activity

  • Antipsychotic agents (Chlorpromazine) + Antiparkinsonian drugs (Trihexyphenidyl) + Antidepressant (Amitriptyline)

• Drugs exhibiting hypotensive effects

  • Anti-HTN + TCAs → orthostatic hypotension

  • PDE5 inhibitors + nitrates → potentiate hypotensive effects of nitrate

[PHARMACODYNAMIC INTERACTIONS]

Drugs having similar pharmacologic effects [2]

c. Additive depressant effects

[PHARMACODYNAMIC INTERACTIONS]

CNS Depressants:

• Anti-psychotics

• TCAs

• Opioid analgesics

• Most antihistamines

• Sedative-Hypnotics (S/H) and Alcohol (OH)

Result in _______

a. Anticholinergic activity

b. Hypotensive effects

c. Additive depressant effects

d. Synergistic effects

c. Anticholinergic activity

[PHARMACODYNAMIC INTERACTIONS]

Antipsychotic agents (Chlorpromazine) + Antiparkinsonian drugs (Trihexyphenidyl) + Antidepressant (Amitriptyline)

Exhibits ______

a. Hypotensive effects
b. Additive depressant effects
c. Anticholinergic activity
d. Synergistic effects

• Anti-HTN + TCAs

• PDE5 inhibitors + nitrates

[PHARMACODYNAMIC INTERACTIONS]

Drugs exhibiting hypotensive effects [2]

b. Orthostatic hypotension

[PHARMACODYNAMIC INTERACTIONS]

Anti-hypertensives (Anti-HTN) + Tricyclic antidepressants (TCAs) result in:

a. Hypertension
b. Orthostatic hypotension
c. Tachycardia
d. Serotonin syndrome

b. Potentiate hypotensive effects of nitrate

[PHARMACODYNAMIC INTERACTIONS]

PDE5 inhibitors + nitrates → _____

a. Decreased hypotensive effects
b. Potentiate hypotensive effects of nitrate
c. No interaction
d. Hypertensive crisis

• Digoxin – Diuretics

• Ace Inibitors (ACEi) and K-sparing diuretics

• Lithium – Diuretics

[PHARMACODYNAMIC INTERACTIONS]

Drugs that exhibits Alteration of Electrolyte Concentrations [3]

a. True

[PHARMACODYNAMIC INTERACTIONS]

Diuretics cause excessive loss of potassium, making the heart more sensitive to the effects of cardiac glycosides and arrhythmia, since a decrease in potassium concentration increases Digoxin effects.

a. True
b. False

a. Potassium

Diuretics cause excessive loss of ______

a. Potassium

b. Sodium

a. Increases Digoxin effects

[PHARMACODYNAMIC INTERACTIONS]

A decrease in potassium concentration → _______

a. Increases Digoxin effects

b. Decreases Digoxin effects

b. Hyperkalemia

[PHARMACODYNAMIC INTERACTIONS]

ACE inhibitors + Potassium-sparing diuretics increases potassium serum concentration leading to ______

a. Hypokalemia

b. Hyperkalemia

c. Hyponatremia

d. Hypercalcemia

c. Both a and b

• Diuretic therapy

• Sodium-restructed diet

[PHARMACODYNAMIC INTERACTIONS]

Lithium should not be used in patients on _____

a. Diuretic therapy

b. Sodium-restricted diet

c. Both a and b

b. Decreased renal clearance of Lithium, increased activity

[PHARMACODYNAMIC INTERACTIONS]

Decreased sodium levels lead to:

a. Increased renal clearance of Lithium, decreased activity

b. Decreased renal clearance of Lithium, increased activity

c. No change in Lithium levels

d. Decreased Lithium toxicity

• Atropine-like reaction

• Tremors

• Convulsions

• Hyperthermia

• Vascular collapse

[PHARMACODYNAMIC INTERACTIONS]

MAOIs + TCAs may result in_____ [5]