50 concise modules: definitions, key facts, and classroom review questions.
Pain is the primary symptom that brings a patient to the physician. In this section, we examine the entire arsenal of pharmacological pain control: how to block impulses in the periphery, prevent them from reaching the spinal cord, or alter perception in the cerebral cortex.
The section covers local anesthetics (from procaine to bupivacaine), opioid analgesics along with the organization of the antinociceptive system, as well as a vast range of non-steroidal anti-inflammatory drugs (NSAIDs). In addition, it compiles disease-modifying antirheumatic drugs (DMARDs), anti-gout medications (allopurinol, colchicine), and agents acting on sensory nerve endings (astringents, demulcents, irritants).
During tests and exams, examiners are most rigorous about the differences in the sites of action of opioids (spinal and supraspinal mechanisms), the selectivity of NSAIDs toward COX-1 and COX-2, as well as the clinical presentation of acute morphine poisoning and the use of antagonists. Master the mechanisms and side effects: the ability to wisely choose between ketorolac, paracetamol, or fentanyl is the foundation of clinical practice.
Why is an anesthetic weakly effective during tooth extraction against the background of purulent inflammation?
In inflamed tissues, the environment becomes acidic. Anesthetics are weak bases, and in an acidic environment, they convert into an ionized form, losing their ability to penetrate through the nerve membrane to sodium channels.
Why is cocaine practically unused in modern medicine?
Due to its ability to be instantly absorbed through mucous membranes, it exerts a strong resorptive effect. This is associated with an unacceptably high risk of toxic effects (convulsions, respiratory depression) and rapid dependence formation.
Can tetracaine be used for infiltration or nerve block anesthesia?
No. Due to its ultra-high toxicity and ability to be rapidly absorbed into the bloodstream, it is used exclusively for surface (topical) anesthesia of mucous membranes.
Why is benzocaine not used for injection anesthesia?
This is due to its physicochemical properties. Benzocaine is practically insoluble in water, making it impossible to prepare a safe and effective aqueous solution for injection from it.
Why is procaine unsuitable for surface (terminal) anesthesia?
The drug penetrates intact mucous membranes very poorly. A high concentration (10%) is required to produce an effect, which makes this method impractical.
Why is it necessary to add epinephrine to trimecaine?
The addition of epinephrine pursues two main goals: reducing the systemic toxicity of the drug by decreasing its absorption into the bloodstream and significantly prolonging the local anesthetic effect.
Master the entire topic in the «Pharmacology» course
This is a summary. The course covers everything tested in classes and exams.
5,304 pages of study guides on all topics
Assignments and quizzes after every topic — just like in a colloquium