Most common dose related side effect of salbutamol is:
**Core Concept**
Salbutamol, a short-acting beta-2 agonist, is a commonly used bronchodilator in the management of asthma and chronic obstructive pulmonary disease (COPD). Its therapeutic effects are primarily due to its ability to activate beta-2 adrenergic receptors in the airway smooth muscle, leading to bronchodilation.
**Why the Correct Answer is Right**
The most common dose-related side effect of salbutamol is **cardiac arrhythmias**, particularly **tachycardia**. This occurs due to the non-selective activation of beta-1 and beta-2 adrenergic receptors, leading to an increase in heart rate and contractility. The non-selective activation of beta-1 receptors in the heart results in an increase in sympathetic tone, which in turn increases heart rate and cardiac output. This effect is more pronounced at higher doses of salbutamol.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hypokalemia is not a direct dose-related side effect of salbutamol. While salbutamol can cause a small decrease in potassium levels, this is not the most common dose-related side effect.
* **Option B:** Hyperglycemia is not a direct dose-related side effect of salbutamol. While salbutamol can cause an increase in glucose levels, this is not the most common dose-related side effect.
* **Option C:** Tremors and nervousness are more common side effects of salbutamol, but they are not typically dose-related. They are more likely to occur at therapeutic doses.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the dose-related side effects of salbutamol can be mitigated by using **inhaled corticosteroids** in conjunction with bronchodilators. This combination can reduce the systemic absorption of salbutamol and minimize its dose-related side effects.
**Correct Answer:** A. Cardiac arrhythmias, particularly tachycardia.