CANS Pharmacology & Medications in Aesthetics 1 — Questions and Answers
Question 1: What is the primary mechanism of action of botulinum toxin type A in aesthetic treatments?
- Stimulates acetylcholine release at the neuromuscular junction
- Blocks acetylcholine release at the neuromuscular junction (Correct answer)
- Inhibits norepinephrine uptake at nerve terminals
- Promotes collagen synthesis in the dermis
Correct answer: Blocks acetylcholine release at the neuromuscular junction
Botulinum toxin type A cleaves SNAP-25 protein, preventing acetylcholine vesicle fusion and release at the neuromuscular junction, resulting in temporary muscle paralysis.
Question 2: Which enzyme is the antidote used to dissolve hyaluronic acid filler complications such as vascular occlusion?
- Collagenase
- Elastase
- Hyaluronidase (Correct answer)
- Lipase
Correct answer: Hyaluronidase
Hyaluronidase degrades hyaluronic acid chains and is the only enzymatic reversal agent available for HA-based dermal fillers.
Question 3: The maximum recommended dose of lidocaine WITH epinephrine for local anesthesia in aesthetic procedures is approximately:
- 3 mg/kg
- 5 mg/kg
- 7 mg/kg (Correct answer)
- 10 mg/kg
Correct answer: 7 mg/kg
Lidocaine with epinephrine has a maximum safe dose of approximately 7 mg/kg because epinephrine-induced vasoconstriction slows systemic absorption and reduces toxicity risk.
Question 4: Which topical depigmenting agent is considered the FDA-recognized gold standard for treating post-inflammatory hyperpigmentation?
- Hydrocortisone 1%
- Hydroquinone 4% (Correct answer)
- Tretinoin 0.025%
- Kojic acid 2%
Correct answer: Hydroquinone 4%
Hydroquinone 4% is the gold standard depigmenting agent, working by inhibiting tyrosinase to reduce melanin synthesis in melanocytes.
Question 5: EMLA cream provides topical anesthesia through a eutectic mixture of which two local anesthetics?
- Lidocaine and bupivacaine
- Lidocaine and prilocaine (Correct answer)
- Prilocaine and mepivacaine
- Benzocaine and tetracaine
Correct answer: Lidocaine and prilocaine
EMLA (Eutectic Mixture of Local Anesthetics) contains lidocaine 2.5% and prilocaine 2.5%, which together achieve a lower melting point and better skin penetration than either agent alone.
Question 6: Tretinoin (retinoic acid) exerts its primary aesthetic benefits by:
- Inhibiting melanin synthesis by directly blocking tyrosinase
- Binding nuclear retinoic acid receptors to promote keratinocyte turnover and collagen synthesis (Correct answer)
- Reducing sebum production by permanently shrinking sebaceous glands
- Acting as a free radical scavenger to neutralize UV-induced oxidative damage
Correct answer: Binding nuclear retinoic acid receptors to promote keratinocyte turnover and collagen synthesis
Tretinoin binds nuclear retinoic acid receptors (RARs), upregulating genes that accelerate epidermal turnover and stimulate dermal fibroblasts to synthesize new collagen.
Question 7: Epinephrine is added to local anesthetic solutions in aesthetic procedures primarily to:
- Reduce the risk of post-procedure infection
- Prolong anesthesia duration and reduce systemic absorption via vasoconstriction (Correct answer)
- Enhance the intrinsic potency of the anesthetic molecule
- Prevent post-procedure edema and swelling
Correct answer: Prolong anesthesia duration and reduce systemic absorption via vasoconstriction
Epinephrine causes local vasoconstriction, which slows vascular uptake of the anesthetic, prolongs its duration of action, reduces bleeding, and lowers the risk of systemic toxicity.
CANS Pharmacology & Medications in Aesthetics 1
What is the primary mechanism of action of botulinum toxin type A in aesthetic treatments?