Cosentyx is a biologic medication that is used to treat a variety of inflammatory conditions such as psoriasis, psoriatic arthritis, and ankylosing spondylitis. According to the sources provided, it is possible for Cosentyx levels to fluctuate over time.

The first source, Drug Patent Watch [1], provides information about the patent status of Cosentyx. It does not provide any information about Cosentyx levels fluctuating over time.

The second source, a study published in the Journal of Clinical Pharmacology [2], states that Cosentyx levels can vary over time. The study found that after repeated dosing, Cosentyx levels increased with each dose and then plateaued. However, the study also found that there was significant variability in the levels of Cosentyx between patients.

The third source, the Cosentyx website [3], provides a FAQ section for patients with ankylosing spondylitis. The website states that Cosentyx levels can vary between individuals and that the effectiveness of the medication may also vary over time.

In summary, while the sources provided do not all directly address the question of whether Cosentyx levels can fluctuate over time, the study published in the Journal of Clinical Pharmacology and the information provided on the Cosentyx website suggest that levels can vary between patients and may also fluctuate over time. It is important for patients to discuss any concerns about their medication levels with their healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/COSENTYX
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065121/
[3] https://www.cosentyx.com/ankylosing-spondylitis/faq