Unit 7: Allergies, Side Effects, and Adverse Effects

What is a drug allergy?

An immunologically mediated hypersensitivity reaction that recurs upon re-exposure.

What is anaphylaxis?

A rapid, systemic, life-threatening allergic reaction requiring IM epinephrine.

First-line treatment for airway-threatening allergic reaction?

Intramuscular epinephrine.

Most common antibiotics causing drug allergies?

β-lactams (penicillins, cephalosporins).

ACE inhibitors most serious allergy risk?

Angioedema.

Sulfonamides are most associated with which severe reactions?

SJS, TEN, DRESS.

Type I hypersensitivity mechanism?

IgE mediated mast cell degranulation.

Type I onset?

Minutes.

Type I examples?

Anaphylaxis, urticaria, asthma.

Type II mechanism?

IgG/IgM destroy target cells.

Type II example?

Hemolytic anemia.

Type III mechanism?

Immune complex deposition.

Type III example?

Serum sickness.

Type IV mechanism?

T-cell mediated (no antibodies).

Type IV onset?

48–72 hours.

Type IV example?

Contact dermatitis.

SJS hallmark?

Skin blistering + mucosal involvement.

TEN difference from SJS?

More extensive epidermal detachment.

DRESS symptoms?

Rash, fever, lymphadenopathy, organ involvement.

Management of SJS/TEN?

Immediate hospitalization (ICU/burn unit).

Mild (itching, localized rash):

Stop Drug

Oral antihistamines

topical corticosteroids

Moderate (widespread urticaria):

Systemic corticosteroids

monitoring

Severe (airway, hypotension):

IM epinephrine

oxygen

IV fluids

hospitalization

Side effects are typically?

Predictable and dose-related.

Adverse effects are?

Harmful, serious, may require discontinuation.

Can side effects be beneficial?

Yes (diphenhydramine sedation for sleep).

Tetracyclines →

Tooth discoloration, photosensitivity

Fluoroquinolones →

Tendon rupture, QT prolongation

Macrolides →

QT prolongation, GI upset

Warfarin/Heparin →

Bleeding

Beta-blockers →

Hypoglycemia, cold extremities

ACE inhibitors →

Cough, hyperkalemia, angioedema

Spironolactone →

Hyperkalemia, gynecomastia

Loop diuretics →

Ototoxicity, hypokalemia

Opioids →

Respiratory depression, constipation

Benzodiazepines →

Sedation, dependence

Antipsychotics →

EPS, QT prolongation, weight gain

Clozapine →

Agranulocytosis

Metformin →

Lactic acidosis

Statins →

Myopathy, rhabdomyolysis

Bisphosphonates →

Osteonecrosis of jaw

Vancomycin →

Red man syndrome

Aminoglycosides →

Ototoxicity, nephrotoxicity

Sulfonylureas →

Hypoglycemia

Phenytoin →

Gum overgrowth

Carbamazepine →

Hyponatremia

Nitrofurantoin →

Brown urine

A patient develops lip swelling and difficulty breathing after taking amoxicillin. What is the first action?

A) Oral antihistamine
B) Topical steroid
C) IM epinephrine
D) Prednisone tablet

C) IM epinephrine

A patient taking lisinopril reports persistent dry cough. This is:

A) Type I allergy
B) Side effect
C) Type III hypersensitivity
D) Anaphylaxis

B) Side effect

Which drug is MOST associated with tendon rupture?

A) Azithromycin
B) Ciprofloxacin
C) Amoxicillin
D) Doxycycline

B) Ciprofloxacin

A patient develops muscle pain and dark urine while on simvastatin. This suggests:

A) Hypoglycemia
B) Rhabdomyolysis
C) QT prolongation
D) Tendon rupture

B) Rhabdomyolysis

Which reaction requires ICU or burn unit care?

A) Mild rash
B) Urticaria
C) Stevens-Johnson syndrome
D) Sedation

C) Stevens-Johnson syndrome

Which medication causes orange urine?

A) Nitrofurantoin
B) Phenazopyridine
C) Metformin
D) Aspirin

B) Phenazopyridine

Which medication causes agranulocytosis?

A) Risperidone
B) Clozapine
C) Quetiapine
D) Haloperidol

B) Clozapine

A patient on spironolactone should be monitored for:

A) Hypokalemia
B) Hyperkalemia
C) Hypoglycemia
D) Hyponatremia

B) Hyperkalemia

Red man syndrome is associated with:

A) Gentamicin
B) Vancomycin
C) Ceftriaxone
D) Metronidazole

B) Vancomycin

Which is a predictable side effect of opioids?

A) Anaphylaxis
B) Respiratory depression
C) Serum sickness
D) DRESS

B) Respiratory depression

ACE inhibitors risk?

Angioedema / hyperkalemia

Beta-blockers may mask?

Hypoglycemia

Which causes QT prolongation?

Macrolides / Fluoroquinolones / Antipsychotics

Drug causing osteonecrosis jaw?

Bisphosphonates

Metformin severe adverse effect?

Lactic acidosis

First generation H1 blockers cause?

Sedation

Which causes gynecomastia?

Spironolactone

Which antibiotic causes tooth discoloration?

Tetracyclines

Which drug causes lactic acidosis?

Metformin

Which drug causes ototoxicity (antibiotic class)?

Aminoglycosides

Which antidiabetic causes hypoglycemia?

Sulfonylureas / Insulin

Which antidepressants increase bleeding risk?

SSRIs

Which diuretics cause hearing loss?

Loop diuretics

Which antiepileptic causes gum overgrowth?

Phenytoin

Which reaction is IgE mediated?

Type I

Which hypersensitivity has 48–72 hr onset?

Type IV

Which medication increases tendon rupture risk?

Fluoroquinolones

Which drug class increases risk of venous thromboembolism?

Estrogens / Progestogens

Which drug can cause QT prolongation AND EPS?

Antipsychotics

Which reaction is most life-threatening?

Anaphylaxis

Drugs ending in –afil belong to what class?

PDE-5 inhibitors

Examples of –afil drugs?

Sildenafil, tadalafil, vardenafil, avanafil

Major caution with –afil drugs?

Severe hypotension with nitrates

Drugs ending in –asone are what class?

Corticosteroids

Examples of -asone drugs:

Betamethasone, dexamethasone, fluticasone

–bicin drugs are what type?

Antineoplastic (cytotoxic chemotherapy)

Example of -bicin drug?

Doxorubicin

–bital drugs belong to which class?

Barbiturates (sedatives)

Example of a -bit(al) drug?

Phenobarbital

–caine drugs are?

Local anesthetics

Example of a -caine drug?

Lidocaine

Drugs starting with cef- or ceph- are?

Cephalosporin antibiotics

Example of -cep or -ceph drugs?

Cefdinir

–cillin drugs are?

Penicillin antibiotics

Example of -cillin drugs?

Amoxicillin

–cycline drugs belong to what class?

Tetracycline antibiotics

–dazole drugs treat what?

Anthelmintic / antibiotic / antiprotozoal

Example of -dazole drugs?

Metronidazole

–dipine drugs are?

Calcium channel blockers

Example of -dipine drugs?

Amlodipine

–drone drugs are?

Bisphosphonates

–prazole drugs are?

Proton pump inhibitors (PPIs)

Example of -prazole drugs?

Omeprazole