The clinic nurse is preparing to administer an intradermal injection. Which needle and gauge are most appropriate for this procedure?

Correct Answer: A

Rationale: The correct answer is A: ¾ to ⅛-inch needle, 25 to 27 gauge. 1. For intradermal injections, a short needle length (¾ to ⅛ inch) is required to deliver the medication into the dermis layer beneath the epidermis. 2. A smaller gauge needle (25 to 27 gauge) is ideal for intradermal injections to minimize tissue damage and ensure accurate delivery into the dermal layer. 3. Choice B is incorrect as a longer needle length is not suitable for intradermal injections and larger gauge needles may cause tissue trauma. 4. Choice C is incorrect as a 20 to 21 gauge needle is too large for intradermal injections and can lead to inaccurate medication placement. 5. Choice D is incorrect as a tuberculin syringe is not typically used for standard intradermal injections due to its larger size and volume capacity.

Correct Answer: C

Rationale: The correct answer is C: Weakly acidic drugs. In basic urine (pH > 7), weakly acidic drugs will be more ionized and therefore less reabsorbed in the renal tubules, leading to faster excretion. Weakly basic drugs (A) will be more unionized in basic urine and reabsorbed. Lipid-soluble drugs (B) are typically reabsorbed regardless of urine pH. Protein-conjugated substances (D) are usually metabolized before excretion, so urine pH has minimal impact on their excretion rate.

Correct Answer: A

Rationale: Passive diffusion involves movement of drug molecules across the cell membrane lipid layer from an area of high concentration to low concentration, without the need for energy or carrier proteins. Lipid-soluble drugs can easily diffuse through the lipid bilayer due to their hydrophobic nature. This process is driven by the concentration gradient and follows Fick's law of diffusion. Ion channels (B) facilitate the movement of ions, not drugs. Methyl residues (C) and transport proteins (D) are not directly involved in passive diffusion of drugs.

Correct Answer: A

Rationale: The correct answer is A: Amphetamine. Beta-blockers like Propranolol, Carvedilol, and Timolol work by blocking the effects of adrenaline on beta receptors, reducing heart rate and blood pressure. Amphetamine, on the other hand, is a stimulant drug that works by increasing the release of neurotransmitters like dopamine and norepinephrine, unrelated to beta receptor blockade. Therefore, Amphetamine is not a beta-blocker.

Correct Answer: C

Rationale: Certainly! Prazosin is an alpha-1 antagonist, which means it blocks the activation of alpha-1 adrenergic receptors. By blocking these receptors, prazosin leads to vasodilation and reduced peripheral vascular resistance, ultimately lowering blood pressure. The other options are not correct because prazosin does not act as a beta-1 antagonist (B), beta-2 agonist (D), or alpha-1 agonist (A) in the context of treating hypertension.