NBDHE NBDHE Pharmacology in Dental Hygiene 5 — Questions and Answers
Question 1: A patient with a penicillin allergy (hives, urticaria) requires antibiotic prophylaxis before a dental procedure. Which regimen is recommended?
- Cephalexin 2 g orally
- Clindamycin 600 mg orally
- Azithromycin 500 mg orally (Correct answer)
- Amoxicillin 2 g orally
Correct answer: Azithromycin 500 mg orally
Current AHA guidelines recommend azithromycin or clarithromycin 500 mg orally for patients allergic to penicillin who can take oral medications.
Question 2: Which mechanism explains corticosteroid-induced osteoporosis relevant to dental implant planning?
- Increased osteoblast activity and bone deposition
- Decreased intestinal calcium absorption and increased osteoclast activity (Correct answer)
- Stimulation of parathyroid hormone secretion only
- Direct inhibition of osteoclasts
Correct answer: Decreased intestinal calcium absorption and increased osteoclast activity
Corticosteroids reduce intestinal calcium absorption, increase renal calcium excretion, and enhance osteoclast activity while suppressing osteoblasts, leading to bone loss.
Question 3: A patient is prescribed chlorhexidine gluconate 0.12% oral rinse. Which instruction is most important to maximize its efficacy?
- Use immediately before brushing teeth
- Rinse vigorously for 30 seconds after meals
- Avoid eating, drinking, and rinsing for 30 minutes after use (Correct answer)
- Dilute with equal parts water to reduce staining
Correct answer: Avoid eating, drinking, and rinsing for 30 minutes after use
Eating, drinking, or rinsing after chlorhexidine use washes away the drug before it can bind to oral surfaces and exert its substantive antimicrobial effect.
Question 4: Which drug class used to treat hypertension is most commonly associated with drug-induced gingival overgrowth?
- ACE inhibitors (e.g., lisinopril)
- Thiazide diuretics (e.g., hydrochlorothiazide)
- Calcium channel blockers (e.g., nifedipine) (Correct answer)
- Beta-blockers (e.g., metoprolol)
Correct answer: Calcium channel blockers (e.g., nifedipine)
Calcium channel blockers, particularly nifedipine, are the most common antihypertensive drugs associated with gingival overgrowth due to altered gingival fibroblast activity.
Question 5: A patient taking metformin for type 2 diabetes is scheduled for a procedure requiring IV contrast dye. Why is this dental consideration important?
- Metformin reduces local anesthetic efficacy
- Metformin must be withheld to prevent lactic acidosis if contrast-induced nephrotoxicity occurs (Correct answer)
- Metformin causes additive sedation with nitrous oxide
- Metformin increases bleeding time requiring altered antibiotic prophylaxis
Correct answer: Metformin must be withheld to prevent lactic acidosis if contrast-induced nephrotoxicity occurs
Contrast media can cause acute kidney injury; if renal function declines, metformin accumulates and increases the risk of potentially fatal lactic acidosis.
Question 6: Which dental drug is most likely to cause a false-positive result on a urine drug screen for amphetamines?
- Codeine
- Epinephrine 1:100,000 in local anesthetic
- Phentermine (appetite suppressant)
- Pseudoephedrine in OTC decongestants (Correct answer)
Correct answer: Pseudoephedrine in OTC decongestants
Pseudoephedrine, a sympathomimetic found in OTC decongestants that patients may take before dental visits, is a known cause of false-positive amphetamine urine screens.
Question 7: Which systemic effect should the dental hygienist anticipate when a patient is administered 0.3 mg of epinephrine via accidental intravascular injection during inferior alveolar nerve block?
- Immediate hypotension and bradycardia
- Tachycardia, palpitations, and transient hypertension (Correct answer)
- Bronchoconstriction and wheezing
- Prolonged sedation and respiratory depression
Correct answer: Tachycardia, palpitations, and transient hypertension
Intravascular epinephrine injection causes rapid adrenergic stimulation resulting in tachycardia, palpitations, anxiety, and a transient rise in blood pressure.
NBDHE NBDHE Pharmacology in Dental Hygiene 5
A patient with a penicillin allergy (hives, urticaria) requires antibiotic prophylaxis before a dental procedure.
Which regimen is recommended?