Common side effects of nilutamide include hot flashes, nausea, diarrhea, decreased libido, erectile dysfunction, and fatigue. It may also cause liver dysfunction (elevated liver enzymes), vision problems (like blurred vision), and breathing difficulties. Some individuals may experience skin rashes or gynecomastia (enlargement of breast tissue).

Nilutamide has several important warnings. It can cause severe liver toxicity, so regular monitoring of liver function is recommended during treatment. Additionally, it can lead to interstitial lung disease, causing lung inflammation, which may result in cough, fever, and shortness of breath. Nilutamide may also cause visual disturbances, especially in the first few weeks of treatment, and patients should avoid driving or operating machinery until they know how the drug affects them. The medication should be used with caution in individuals with liver disease or a history of lung problems.

In the event of an overdose, symptoms may include nausea, vomiting, drowsiness, and liver toxicity. Immediate medical attention is required to manage an overdose, which may involve supportive care, including monitoring liver function and symptomatic treatment. If an overdose is suspected, seek emergency care immediately.