 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  flow problems in the fingers or toes (such as coldness, numbness, pain, or skin color changes), unusual wounds on the fingers or toes, fast/pounding/irregular heartbeat, mental/mood/behavior changes (such as agitation, aggression, mood swings, abnormal thoughts, thoughts of suicide), uncontrolled muscle movements (such as twitching, shaking), sudden outbursts of words/sounds that are hard to control, vision changes (such as blurred vision), slow healing sores/ulcers on the tips of fingers/toes. Get medical help right away if you have any very serious side effects, including: fainting, seizure, symptoms of a heart attack (such as chest/jaw/left arm pain, shortness of breath, unusual sweating), symptoms of a stroke (such as weakness on one side of the body, trouble speaking, sudden vision changes, confusion). Rarely, males (including young boys and teens) may have a painful or prolonged erection lasting 4 or more hours while using this medication. Caregivers/parents should also be watchful for this serious side effect in boys. If a painful or prolonged erection occurs, stop using this drug and get medical help right away, or permanent problems could occur. </s>