# Situation: A 62-year-old man who weighs 80 kg is receiving his first dose of an intravenous (IV) antibiotic on the medical ward. Ten minutes into the infusion, he develops generalized hives, hoarseness, and wheezing; his blood pressure is 80/50 mmHg and heart rate 96/min. He takes metoprolol daily for hypertension. The infusion has been stopped and help has been called. His wife asks why the nurse injected the adrenaline (epinephrine) into his thigh muscle instead of pushing the same 1 mg/mL solution into his IV line. Which explanation is accurate?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629728  
> language: ko  
> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 62-year-old man who weighs 80 kg is receiving his first dose of an intravenous (IV) antibiotic on the medical ward. Ten minutes into the infusion, he develops generalized hives, hoarseness, and wheezing; his blood pressure is 80/50 mmHg and heart rate 96/min. He takes metoprolol daily for hypertension. The infusion has been stopped and help has been called.

His wife asks why the nurse injected the adrenaline (epinephrine) into his thigh muscle instead of pushing the same 1 mg/mL solution into his IV line. Which explanation is accurate?

## 보기

1. The thigh muscle absorbs it slowly, so its effect lasts longer there
2. A vein route gives a slower onset than the thigh muscle does
3. A vein route is saved for when the airway has already fully closed
4. Pushed into a vein at that strength, it can cause fatal heart rhythms **✔ 정답**

**정답: 4**

## 해설

Intramuscular adrenaline in the mid-outer thigh is absorbed quickly and is safe at the anaphylaxis dose. An undiluted 1 mg/mL IV push produces a sudden high level that can cause ventricular dysrhythmias, severe hypertension, and myocardial ischemia. IV adrenaline in anaphylaxis is given only as a diluted, monitored infusion by experienced staff for shock that does not respond to intramuscular doses.

## 심화 해설

Why the thigh and not the vein
In anaphylaxis, the first-line drug is adrenaline (epinephrine) given intramuscularly into the mid-outer thigh. This route is absorbed quickly and is safe at the anaphylaxis dose. Pushing the same undiluted 1 mg/mL solution into a vein produces a sudden, very high blood level. An undiluted IV push of 1 mg/mL adrenaline can cause fatal ventricular dysrhythmias, severe hypertension, and myocardial ischemia, which is why the thigh muscle was used.

Why intramuscular adrenaline works well
The thigh muscle has a rich blood supply, so adrenaline injected there reaches the circulation within minutes. Its alpha-adrenergic effects constrict blood vessels and raise blood pressure, while its beta-adrenergic effects relax the airways and reduce swelling and the release of inflammatory mediators. This man has hives, hoarseness, wheezing, and a blood pressure of 80/50 mmHg, which together show severe anaphylaxis. Intramuscular adrenaline should be given without delay, and repeated if there is no improvement.

When IV adrenaline is used
IV adrenaline in anaphylaxis is reserved for shock that does not respond to intramuscular doses and fluid resuscitation. It is given only as a diluted, monitored infusion by experienced staff, with continuous cardiac monitoring. It is not a quick push of the 1 mg/mL solution, and it is not reserved for complete airway closure.

Why the other explanations are wrong

| Explanation | Error |
| --- | --- |
| The thigh absorbs it slowly, so the effect lasts longer | Absorption from the thigh is fast, not slow |
| A vein route has a slower onset | IV acts faster; the danger is the sudden high level |
| IV is saved for complete airway closure | IV is a diluted infusion for refractory shock |
| IV push at that strength can cause fatal heart rhythms | Accurate |

Watch out! He takes metoprolol, a beta blocker. Beta blockers can make anaphylaxis more severe and reduce the response to adrenaline. The answer is still intramuscular adrenaline; if he does not respond, the team may consider glucagon, but that does not change why the IV push is dangerous. Positioning him lying flat with legs raised and giving IV fluids also support his blood pressure.

Exam takeaway
Give anaphylaxis adrenaline intramuscularly into the mid-outer thigh; never push the 1 mg/mL solution intravenously. Key point! The concentration on the label matters: the 1 mg/mL strength is for intramuscular use, while IV adrenaline for refractory shock is diluted and infused under monitoring.

## 임상 시나리오

Adrenaline Route in AnaphylaxisWhy the thigh muscle, not an IV push
Give adrenaline (epinephrine) 1 mg/mL intramuscularly into the mid-outer thigh; absorption is fast and the dose is safe.

An undiluted IV push causes a sudden high level that can trigger ventricular dysrhythmias, severe hypertension, and myocardial ischemia.

IV adrenaline is used only as a diluted, monitored infusion for shock not responding to intramuscular doses.

CautionBeta blockers such as metoprolol can make anaphylaxis harder to treat; still give intramuscular adrenaline without delay.

## 핵심 개념

- **Anaphylaxis** — A severe, rapid, life-threatening allergic reaction affecting the skin, airways, and circulation.
- **Adrenaline (epinephrine)** — The first-line drug for anaphylaxis, which raises blood pressure and opens the airways.
- **Intramuscular injection** — Injection of a drug into a muscle, such as the mid-outer thigh for anaphylaxis.
- **Refractory shock** — Shock that does not improve despite initial treatment such as intramuscular adrenaline and fluids.
- **Beta blocker** — A drug such as metoprolol that blocks beta receptors and can reduce the response to adrenaline.

## 같은 주제 문제

- [Situation: A 29-year-old woman has a pre-employment medical examination at a private manuf…](https://mymerci.kr/pages/nclex_q.php?qn_id=629716)
- [Situation: A 29-year-old woman has a pre-employment medical examination at a private manuf…](https://mymerci.kr/pages/nclex_q.php?qn_id=629717)
- [Situation: A 29-year-old woman has a pre-employment medical examination at a private manuf…](https://mymerci.kr/pages/nclex_q.php?qn_id=629718)
- [Situation: A 29-year-old woman has a pre-employment medical examination at a private manuf…](https://mymerci.kr/pages/nclex_q.php?qn_id=629719)
- [Situation: A 34-year-old man was diagnosed with human immunodeficiency virus (HIV) infecti…](https://mymerci.kr/pages/nclex_q.php?qn_id=629720)
- [Situation: A 34-year-old man was diagnosed with human immunodeficiency virus (HIV) infecti…](https://mymerci.kr/pages/nclex_q.php?qn_id=629721)
- [Situation: A 34-year-old man was diagnosed with human immunodeficiency virus (HIV) infecti…](https://mymerci.kr/pages/nclex_q.php?qn_id=629722)
- [Situation: A 41-year-old man is admitted to the medical ward with weakness that began in b…](https://mymerci.kr/pages/nclex_q.php?qn_id=629723)

---

More free questions: [기출문제](https://mymerci.kr/)

_학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._