 <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]  arms/legs, discolored teeth, mental/mood changes (such as confusion, anxiety, irritability, depression), difficult/painful swallowing, heartburn, fast/pounding heartbeat, ringing in the ears, frequent/painful urination, stiff/painful neck, signs of kidney problems (such as change in the amount of urine), signs of infection (such as a sore throat that doesn't go away, or a fever), easy bruising/bleeding, unusual weakness/tiredness, seizures, chest pain, symptoms of liver disease (such as loss of appetite, severe stomach/abdominal pain, yellowing eyes/skin, dark urine). This product commonly causes dark stools that are usually not serious. However, you may not be able to tell this effect apart from blood in the stool, which could be a sign of a serious condition. Tell your doctor right away if you have dark stools. Tetracycline may rarely cause increased pressure around the brain (intracranial hypertension-IH). The risk of this side effect is greater for women of childbearing age who are overweight or who have had IH in the past. If IH develops, it usually goes away after tetracycl </s>