Pharmacology & Pain Control Flashcards
6 cards from real MJDF practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pharmacology & Pain Control flashcards as text
What is the action of vasopressin (felypressin) as a vasoconstrictor in prilocaine?
Answer: Vasoconstriction via V1 receptor activation — does not stimulate adrenergic receptors, safer in certain cardiac conditions
Felypressin (synthetic vasopressin) causes vasoconstriction through vascular V1 receptors without adrenergic stimulation, making it safer than adrenaline in patients with specific cardiac arrhythmias or phaeochromocytoma.
What is the significance of prilocaine's metabolite orthotoluidine?
Answer: Converts haemoglobin to methaemoglobin (methaemoglobinaemia) — risk in large doses, neonates, or G6PD deficiency
Orthotoluidine (prilocaine metabolite) oxidises haemoglobin iron from Fe²⁺ to Fe³⁺ (methaemoglobin), which cannot carry oxygen; this is clinically significant in high doses and in at-risk groups (G6PD deficiency, neonates).
Which antibiotic is specifically contraindicated in children under 12 due to dental staining?
Answer: Tetracycline and doxycycline
Tetracyclines (tetracycline, doxycycline) are contraindicated in children under 12 and in pregnancy because they chelate with calcium during tooth mineralisation, causing permanent intrinsic yellow-brown staining.
What is the recommended approach for managing a dental patient on warfarin requiring extraction?
Answer: Check INR; if ≤3.5, proceed without stopping warfarin with local haemostatic measures (sutures, pack, tranexamic acid)
Current SDCEP/NICE guidance recommends checking INR within 24–72 hours pre-operatively; if ≤3.5, extraction can proceed safely in general practice without stopping warfarin, using local haemostatic measures.
What is the clinical significance of the QT interval in the context of dental drug prescribing?
Answer: Certain drugs (e.g., erythromycin, azithromycin, moxifloxacin) can prolong QT interval, increasing risk of potentially fatal torsades de pointes arrhythmia
Several antibiotics and other drugs prescribed in dentistry can prolong the QT interval, potentially triggering torsades de pointes; caution is required in patients with pre-existing long QT syndrome or those on other QT-prolonging drugs.
What distinguishes a Type I (IgE-mediated) hypersensitivity reaction to penicillin from a Type IV reaction?
Answer: Type I is immediate (minutes), IgE/mast cell-mediated, with urticaria/anaphylaxis; Type IV is delayed (48–72 h), T-cell-mediated, with rash
Type I (immediate) reactions are IgE-mediated, occur within minutes of exposure, and can cause anaphylaxis; Type IV (delayed) are T-cell-mediated, appearing 48–72 hours after exposure as a maculopapular rash.