Cosentyx is a medication used to treat plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis. It works by blocking a protein called interleukin-17A, which is involved in the inflammatory process that causes these conditions [2]. The dosage of Cosentyx may need to be adjusted for several reasons.

Firstly, the initial dosage of Cosentyx may not be effective for some patients, and the dosage may need to be increased. According to the manufacturer's website, the recommended initial dosage for plaque psoriasis is 300 mg, given as two subcutaneous injections of 150 mg each, at weeks 0, 1, 2, 3, and 4, followed by a maintenance dosage of 300 mg every 4 weeks [2]. However, if a patient does not achieve adequate response after 16 weeks of treatment, the dosage may be increased to 300 mg every 2 weeks [2]. Similarly, for psoriatic arthritis and ankylosing spondylitis, the recommended initial dosage is 150 mg every 4 weeks, but the dosage may be increased to 300 mg every 4 weeks if the response is inadequate [2].

Secondly, the dosage of Cosentyx may need to be adjusted if a patient experiences adverse effects. Common side effects of Cosentyx include upper respiratory infections, diarrhea, and injection site reactions [3]. If a patient experiences severe adverse effects, the dosage may need to be decreased or the treatment may need to be discontinued [3].

Lastly, the dosage of Cosentyx may need to be adjusted if a patient has certain medical conditions or is taking certain medications. According to Drug Patent Watch, patients with moderate or severe liver impairment should receive a reduced dosage of Cosentyx [1]. Additionally, certain medications, such as immunosuppressants, may increase the risk of infections when taken with Cosentyx, and the dosage may need to be adjusted accordingly [3].

In conclusion, the dosage of Cosentyx may need to be adjusted for various reasons, including inadequate response, adverse effects, and certain medical conditions or medications. Patients should follow their healthcare provider's instructions regarding dosage adjustments and report any adverse effects or changes in their medical conditions.

Sources:
[1] Drug Patent Watch. Cosentyx. Retrieved from https://www.drugpatentwatch.com/p/biologics/tradename/COSENTYX
[2] Cosentyx. Treatment and Dosing. Retrieved from https://www.cosentyx.com/plaque-psoriasis/treatment-dosing
[3] Healthline. Cosentyx Dosage: An Overview. Retrieved from https://www.healthline.com/health/drugs/cosentyx-dosage