How does an antihistamine work?
By blocking the effects of histamine in the body
By reducing inflammation in the body
By increasing the production of histamine in the body
By stimulating the immune system
The Correct Answer is A
A) By blocking the effects of histamine in the body:
Antihistamines are pharmacological agents that work by antagonizing the effects of histamine, a chemical mediator released by mast cells and basophils in response to allergens or other triggers. Histamine contributes to various allergic symptoms such as itching, sneezing, nasal congestion, and watery eyes. Antihistamines exert their effects by competitively binding to histamine receptors (specifically H1 receptors) on target cells, thereby preventing histamine from binding and exerting its physiological effects. By blocking histamine receptors, antihistamines inhibit the action of histamine, leading to the alleviation of allergy symptoms.
B) By reducing inflammation in the body:
While some medications, such as corticosteroids, exert anti-inflammatory effects by suppressing the immune response and inhibiting the production of inflammatory mediators, antihistamines primarily target histamine receptors and do not directly reduce inflammation. Although histamine release can contribute to inflammation, antihistamines mitigate allergic symptoms primarily by blocking the action of histamine rather than by directly reducing inflammation.
C) By increasing the production of histamine in the body:
This statement is inaccurate. Antihistamines do not increase the production of histamine; instead, they counteract the effects of histamine by blocking its activity at receptor sites. The primary mechanism of action of antihistamines involves blocking histamine receptors to prevent histamine from exerting its physiological effects.
D) By stimulating the immune system:
Antihistamines do not stimulate the immune system. Instead, they act as antagonists to histamine receptors, thereby inhibiting histamine-induced responses. While histamine is involved in immune responses and allergic reactions, antihistamines do not directly modulate immune function or stimulate immune activity. Their primary role is to alleviate allergy symptoms by blocking the effects of histamine."
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is ["675"]
Explanation
1. Convert client weight from pounds to kilograms (kg):
We know 1 kg = 2.205 pounds.
Client weight (kg) = 198 lb / 2.205 lb/kg = 90 kg (round to nearest whole number for this calculation).
2. Calculate the total daily dosage:
Prescribed dosage per kg per day: 15 mg/kg/day
Client weight (kg): 90 kg (rounded value from step 1)
Total daily dosage (mg): Dosage (mg/kg/day) x Client weight (kg)
Total daily dosage (mg): 15 mg/kg/day x 90 kg = 1350 mg/day
3. Since the dosage is divided equally every 12 hours, calculate the amount per dose:
Frequency of administration: Every 12 hours
Total daily dosage (mg): 1350 mg/day
Dosage per dose (mg) = Total daily dosage (mg) / Frequency (doses/day)
Dosage per dose (mg) = 1350 mg/day / 2 doses/day
Dosage per dose (mg) = 675 mg/dose (round to nearest whole number as requested)
Therefore, the nurse should administer approximately 675 mg of vancomycin with each dose.
Correct Answer is A
Explanation
A) Pulmonary artery:
The pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation. This is the correct starting location for blood flow from the heart to the lungs in the pulmonary circulation.
B) Left atrium:
The left atrium receives oxygenated blood from the pulmonary veins and pumps it into the left ventricle, not from the right ventricle to the lungs.
C) Left ventricle:
The left ventricle pumps oxygenated blood into the systemic circulation, not from the right ventricle to the lungs.
D) Pulmonary veins:
The pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart, not from the right ventricle to the lungs."
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