If you have thrombocythemia or thrombocytosis:
If you're taking medicines to lower your platelet count, tell your doctor or dentist about them before any surgical or dental procedures. These medicines thin your blood and may increase bleeding during these procedures.
Medicines that thin the blood also may cause internal bleeding. Signs of internal bleeding include bruises, bloody or tarry-looking stools, pink or bloody urine, increased menstrual bleeding, bleeding gums, and nosebleeds. Contact your doctor right away if you have any of these signs.
Avoid over-the-counter pain medicines such as ibuprofen (except Tylenol®). These medicines may raise your risk of bleeding in the stomach or intestines and may limit the effect of aspirin. Be aware that cold and pain medicines and other over-the-counter products may contain ibuprofen.
Source: National Heart, Lung, and Blood Institute, National Institutes of Health.