What are some therapeutic uses of patches?

The therapeutic uses of patches indeed encompass a range of clinical applications, making them versatile delivery systems for medication. Patches provide a controlled method of drug delivery through the skin, allowing for sustained release over time. This method benefits conditions that require stable blood levels of medication and can improve patient compliance due to their non-invasive nature.

In the context of angina, transdermal patches containing nitrates, for example, are used to relieve chest pain by dilating the blood vessels. Allergy testing often employs specialized patches that allow for a controlled exposure to allergens to assess reactions. Additionally, smoking cessation patches deliver nicotine in a gradual manner, helping to mitigate withdrawal symptoms and cravings as individuals try to quit smoking.

The other choices highlight important therapeutic areas, but they do not directly align with the primary uses of patch formulations as effectively as the selected answer. For example, while some patches might be used for conditions like depression or insomnia, they are not as commonly employed as a systemic delivery method for these issues compared to other forms of medication. Thus, option B stands out due to its alignment with established therapeutic applications of patches.