The nurse is counseling a woman who will be starting rifampin (Rifadin) as part of antitubercular therapy. The patient is currently taking oral contraceptives. Which statement is true regarding rifampin therapy for this patient?

Correct Answer: C

Rationale: The correct answer is C: Oral contraceptives are less effective while the patient is taking rifampin. Rifampin induces hepatic enzymes, which can accelerate the metabolism of oral contraceptives, leading to decreased contraceptive efficacy. This can result in breakthrough bleeding and potential contraceptive failure. It is important to advise the patient to use additional non-hormonal contraceptive methods while on rifampin therapy to prevent unintended pregnancy. Incorrect answer explanations: A: Women do not have a high risk for thrombophlebitis while on rifampin. Rifampin is not known to directly increase the risk of thrombophlebitis. B: A higher dose of rifampin is not necessary because of the contraceptive. Rifampin does not interact with oral contraceptives in a way that requires a higher dose. D: The incidence of adverse effects is not necessarily greater if the two drugs are taken together. Adverse effects are more related to individual drug reactions rather than a

Correct Answer: D

Rationale: The correct answer is D because most local anesthetic agents consist of all three components: a lipophilic group (often an aromatic ring) for membrane penetration, an intermediate chain (usually containing an ester or amide) for linkage to the lipophilic group, and an amino group for interaction with the sodium channels. A is correct as the lipophilic group aids in crossing the lipid-rich cell membrane. B is correct as the intermediate chain connects the lipophilic group and amino group. C is correct as the amino group interacts with sodium channels to block nerve conduction. Therefore, all three components are essential for the local anesthetic mechanism of action.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Physostigmine is a cholinomimetic agent as it acts by inhibiting acetylcholinesterase, leading to increased acetylcholine levels. 2. Acetylcholine is a neurotransmitter that activates cholinergic receptors, mimicking the effects of the parasympathetic nervous system. 3. Physostigmine is used in conditions like myasthenia gravis and glaucoma to enhance cholinergic activity. 4. Edrophonium is a short-acting acetylcholinesterase inhibitor used for diagnostic purposes, not a direct-acting cholinomimetic. 5. Carbachol is a non-selective cholinergic agonist used in ophthalmology and urology, but not directly related to direct-acting cholinomimetic agents.

Correct Answer: B

Rationale: The correct answer is B because scopolamine is actually more potent than atropine in decreasing bronchial, salivary, and sweat gland secretions. The rationale is that scopolamine, being a tertiary amine, has a greater ability to cross the blood-brain barrier and exert stronger central effects compared to atropine. Scopolamine is also more potent in producing mydriasis and cycloplegia due to its greater affinity for muscarinic receptors in the eye muscles. Additionally, scopolamine has lower effects on the heart, bronchial muscle, and intestines compared to atropine. Therefore, B is the correct choice as scopolamine is not less potent in decreasing bronchial, salivary, and sweat gland secretions.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Sympathomimetics, such as adrenaline or epinephrine, stimulate the sympathetic nervous system, leading to increased heart rate (A), vasoconstriction in the peripheral blood vessels (B), and increased venous return to the heart (C). These effects collectively contribute to an increase in blood pressure. Therefore, all three options are correct as sympathomimetics impact the heart, peripheral resistance, and venous return to regulate blood pressure.