Which of the following is/are true for phenolic germicidal agents:

Correct Answer: C

Rationale: Phenolic germicidal agents are commonly used as disinfectants due to their ability to kill microorganisms. Hexachlorophene is one type of phenolic germicidal agent that has been used as a surgical scrub in the past. It has antiseptic properties and can effectively reduce the number of bacteria on the skin, making it suitable for use in sterile environments such as surgical procedures. While phenolic germicidal agents do possess antibacterial properties, they do not typically have topical anesthetic effects like some other types of disinfectants. Additionally, while phenolic agents are used in various dental procedures, they are not specifically used in root canal therapy. The examples provided in the last statement, formocresol, cresantin, and eugenol, are not phenolic germicidal agents but rather dental materials used for different purposes.

Correct Answer: D

Rationale: Loop diuretics, such as furosemide and bumetanide, work by inhibiting the sodium-potassium-chloride co-transporter in the thick ascending loop of Henle in the kidney. This mechanism of action leads to a significant diuretic effect. Loop diuretics have a rapid onset of action, typically within 30 minutes of administration, and they cause rapid diuresis. This rapid onset and potent diuretic effect make loop diuretics effective in situations requiring rapid removal of excess fluid, such as heart failure exacerbation or acute pulmonary edema.

Correct Answer: A

Rationale: Albuterol is an example of a bronchodilator medication commonly used to treat respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). Bronchodilators work by relaxing the muscles in the airways, which helps to open up the air passages and improve airflow to the lungs. This action can help relieve symptoms like wheezing, shortness of breath, and chest tightness. Albuterol is typically administered via inhalation to provide quick relief during an asthma attack or COPD exacerbation.

Correct Answer: A

Rationale: Rifampicin is a potent inducer of CYP450 enzymes, increasing the metabolism of drugs processed via these pathways.

Correct Answer: C

Rationale: Median effective dose (ED50) is where 50% of subjects respond, typically the curve's midpoint (marked ED50), per pharmacodynamic curves. Beginning lacks response. Ascending leg is below 50%. Descending leg is post-peak. ED50's position defines it, aligning with standard graphs.

Correct Answer: D

Rationale: The most concerning adverse effect for an older adult patient taking a vasodilator for hypertension is hypotension, which is abnormally low blood pressure. Older adults may be more sensitive to the blood pressure-lowering effects of vasodilators due to age-related changes in the cardiovascular system. Hypotension can lead to dizziness, lightheadedness, falls, and even fainting, increasing the risk of injury in older adults. Monitoring blood pressure regularly and adjusting the dosage appropriately are crucial in managing this potential adverse effect in older patients.

Correct Answer: B

Rationale: Methylparaben is a preservative commonly found in local anesthetic solutions. Its function is not as an anesthetic, antioxidant, or antiseptic. Instead, methylparaben is added to local anesthetic solutions as a vasoconstrictor. Vasoconstrictors work by causing blood vessels to narrow, which helps to reduce bleeding and increase the duration and effectiveness of the local anesthetic by slowing down the absorption of anesthesia into the bloodstream.

Correct Answer: C

Rationale: All calcium channel blockers (CCBs) like verapamil and nifedipine are orally active, so that's false. Half-lives vary (e.g., nifedipine ~2-5 hours, diltiazem longer), not uniformly 8-12 hours, making that false. They block L-type voltage-gated calcium channels, reducing vascular and cardiac contractility, a true statement. They relax bronchiolar smooth muscle, not unaffected, so that's false. Dihydropyridines cause reflex tachycardia, not bradycardia. The L-type blockade is their unifying mechanism, key to antihypertensive and antianginal effects.

Correct Answer: D

Rationale: Acute asthma and pneumonia in pregnancy require urgent care. IV crystalloids rehydrate, safe and necessary. High FiO2 (40%) supports oxygenation in asthma/pneumonia, appropriate. Nebulized salbutamol, a beta-agonist, relieves bronchospasm, standard and safe. IV hydrocortisone reduces inflammation, suitable. IV gentamicin, an aminoglycoside, treats pneumonia but is inappropriate due to cephalosporin cross-reactivity risk (angioedema history) and fetal ototoxicity concerns, making it unsafe here. Alternative antibiotics (e.g., macrolides) are preferred, prioritizing maternal and fetal safety.