Nokea
If you inject a drug with a pH of 6.5 and pka of 8.1 into a tissue with a pH of 7.4, to what extent would you expect this drug to be ionized in the tissue?
- A. over 50%
- B. 50%
- C. under 50%
- D. 100%
Correct Answer: A
Rationale: The percentage of ionization of a weak acid or base can be estimated using the Henderson-Hasselbalch equation:
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Depression that occurs during cold winter months would be classified as
- A. baby blues
- B. bipolar disorder
- C. seasonal affective disorder
- D. obsessive-compulsive disorder
Correct Answer: C
Rationale: Seasonal affective disorder (SAD) ties depression to winter-less light, per psychiatry-unlike baby blues (postpartum), bipolar (cycles), or OCD (obsessions). SAD's seasonal link defines it, matching symptoms.
ACE inhibitors…
- A. Block the vasoconstrictor and aldosterone from producing effects of angiotensin II at the receptor site
- B. Blocks stimulation of beta 1 and beta 2 at the receptor sites
- C. Blocks the conversion of angiotensin I to the vasoconstrictor angiotensin II
- D. None of the above
Correct Answer: A
Rationale: ACE inhibitors, such as enalapril and lisinopril, work by blocking the enzyme angiotensin-converting enzyme (ACE), which is responsible for converting angiotensin I into angiotensin II. By inhibiting this conversion, ACE inhibitors prevent the vasoconstrictor and aldosterone-stimulating effects of angiotensin II at the receptor sites. This leads to vasodilation, decreased blood pressure, and reduced aldosterone secretion. This mechanism of action makes ACE inhibitors an important class of medications for managing conditions such as hypertension, heart failure, and chronic kidney disease.
Action of tranexamic acid
- A. antiplatelet
- B. fibrinolytic
- C. antifibrinolytic
- D. anticoagulant
Correct Answer: C
Rationale: Tranexamic acid is an antifibrinolytic agent, which means it works by inhibiting the breakdown of blood clots. It does this by blocking the activation of plasmin, which is responsible for breaking down fibrin clots. This action helps in promoting clot stability and reducing bleeding. Tranexamic acid is commonly used to treat or prevent excessive bleeding in various conditions, such as heavy menstrual bleeding, surgery, trauma, and certain medical procedures.
A local municipality is alerted that low doses of carbon tetrachloride have been dumped into the drinking water. A public health alert is transmitted to all residents of this town. Which of the following signs and symptoms should these residents be aware of?
- A. Convulsions
- B. Eye irritation
- C. Nausea
- D. Stupor
Correct Answer: C
Rationale: Carbon tetrachloride exposure causes nausea , reflecting GI and hepatic toxicity. Convulsions and stupor occur with high doses. Eye irritation and vomiting (E) are less specific. Low-dose ingestion aligns with nausea as a primary symptom.
A 59-year-old man with a history of depression cuts his wrists in a suicide attempt. He is brought to the local emergency department for care. He has bilateral medial 3-cm lacerations through the skin and subcutaneous tissues that will require sutures. A review of his prior medical history indicates an allergy to 2% lidocaine. The most likely explanation for this is which of the following?
- A. Allergic
- B. Mast cell mediated
- C. Neurogenic
- D. Psychogenic
Correct Answer: A
Rationale: Lidocaine allergy causing an issue with suturing suggests an allergic reaction , likely IgE-mediated (overlapping with B, but A is broader). Neurogenic , psychogenic , and vascular (E) don't fit. True local anesthetic allergies are rare but explain this history.