**Core Concept**
Aminophylline is a phosphodiesterase inhibitor used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). Its loading dose is crucial in achieving therapeutic plasma concentrations quickly, which is essential in managing acute asthma exacerbations.

**Why the Correct Answer is Right**
The adult loading dose of aminophylline is typically calculated based on the patient's weight or severity of the condition. The commonly recommended loading dose is 5-7 mg/kg administered over 20-30 minutes. This rapid administration aims to achieve a serum theophylline concentration of 10-20 mcg/mL within 1-2 hours. The loading dose should not exceed 500 mg in a single administration to avoid toxicity.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as a loading dose of 2 mg/kg is too low and may not achieve therapeutic plasma concentrations within the desired timeframe.
**Option B:** Incorrect, as a loading dose of 10 mg/kg may lead to excessive serum theophylline concentrations, increasing the risk of toxicity.
**Option C:** Incorrect, as a loading dose of 1 mg/kg is significantly lower than the recommended dose and may not be effective in managing acute asthma exacerbations.

**Clinical Pearl / High-Yield Fact**
When administering aminophylline, it is essential to monitor serum theophylline concentrations regularly to avoid toxicity, which can manifest as nausea, vomiting, headache, and in severe cases, seizures and cardiac arrhythmias.

**Correct Answer: C. 5-7 mg/kg, administered over 20-30 minutes.**