Final answer:
Terbutaline's effectiveness after 48 hours can vary depending on its use for asthma or delaying preterm labor. Its effects for immediate relief of asthma symptoms are short-acting and for preterm labor, usage typically doesn't exceed 48-72 hours due to potential risks.
Step-by-step explanation:
The question regarding the effectiveness of terbutaline after 48 hours pertains to its duration of action in the body, particularly in treating conditions such as asthma or in delaying preterm labor. Terbutaline is a β2-adrenergic agonist that works by relaxing the muscles in the airways to improve breathing and by relaxing the smooth muscle of the uterus to prevent contractions. The duration that terbutaline remains effective can vary based on the individual's response to the medication and the condition being treated. For management of preterm labor, its use is generally limited to 48-72 hours due to potential maternal and fetal side effects with prolonged use beyond this timeframe.
In the context of asthma, terbutaline's bronchodilatory effects are relatively short-acting, and medication is typically administered for immediate relief. While the peak effects of terbutaline occur within hours, these effects tend to wane, and longer-term control of asthma symptoms is typically managed with other types of medications. It's crucial to follow a healthcare provider's instructions on the use of terbutaline and notify them if symptoms persist beyond the expected time of relief.