Pharmacology & Therapeutics Flashcards

A podiatrist prescribes ciprofloxacin for a diabetic foot infection. Which co-medication requires the MOST careful monitoring due to a significant drug interaction?

Answer: Theophylline

Ciprofloxacin inhibits CYP1A2, substantially increasing theophylline plasma levels and risk of toxicity including seizures and arrhythmias.

Capsaicin cream is sometimes applied to feet for peripheral neuropathic pain. What neurotransmitter/receptor system does it target?

Answer: TRPV1 (transient receptor potential vanilloid 1)

Capsaicin binds and desensitizes TRPV1 receptors on C-fiber nociceptors, initially causing burning and then depletion of substance P and pain relief.

In a patient with a sulfa allergy, which topical agent used for burn wounds and diabetic foot ulcers should be avoided?

Answer: Silver sulfadiazine

Silver sulfadiazine contains the sulfonamide moiety sulfadiazine and should be avoided in patients with sulfa drug allergies.

A patient is prescribed oral terbinafine for onychomycosis. Which baseline laboratory test is most important before initiating therapy?

Answer: Liver function tests

Oral terbinafine is hepatotoxic; baseline liver function tests are required, and the drug is contraindicated with pre-existing liver disease.

What is the mechanism of action of hydroxychloroquine when used off-label for inflammatory arthritis affecting the feet?

Answer: Accumulates in lysosomes and raises intracellular pH, impairing antigen processing

Hydroxychloroquine is a weak base that accumulates in lysosomes, raising pH and interfering with antigen processing and TLR signaling.

A patient presents with plantar warts and is treated with topical salicylic acid. What is the mechanism of this keratolytic agent?

Answer: Softens and breaks down keratin by disrupting hydrogen bonds

Salicylic acid is a keratolytic that softens and breaks down the stratum corneum by disrupting hydrogen bonds between keratin fibers.

Which statement about the use of corticosteroid injections in plantar fasciitis is MOST accurate regarding adverse effects?

Answer: Repeated injections risk plantar fascia rupture and fat pad atrophy

Repeated corticosteroid injections into the plantar fascia can weaken collagen structure, leading to fascia rupture and heel fat pad atrophy.