The caffeine in oolong tea might block the affects of dipyridamole (Persantine). Side Effects Concerns and Potential Side Effects. Taking oolong tea along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).Oolong tea contains caffeine. Oolong tea is made from leaves of the same plant that green and black teas come from. Taking oolong tea along with medications that also slow clotting might increase the chances of bruising and bleeding.Stimulant drugs such as nicotine speed up the nervous system. Taking oolong tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Caffeine (contained in oolong tea) and ephedrine are both stimulant drugs. Certain studies have shown that Oolong tea may possibly slow down blood clotting. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking oolong tea along with fluconazole (Diflucan) might increase the risk of caffeine side effects such as nervousness, anxiety, and insomnia.Oolong tea might increase blood sugar. Though many tea enthusiasts suggest drinking oolong tea plain without any additions, you can add two spoonfuls of milk as well as sugar to prepare oolong milk tea.Though oolong tea is said to be safe when eaten in moderate amounts, overconsumption may result in nausea, vomiting or other side effects because of its caffeine content.Though possibly safe during pregnancy, consumption should be in measured amounts as its high caffeine content could take a toll on their health.You can buy oolong tea powder or even tea bags online or at stores selling black or green tea.Article was last reviewed on Avoid taking stimulant drugs along with oolong tea.Stimulant drugs such as cocaine speed up the nervous system. Caffeine Effects If people drink lots of caffeine over a long time period -- including that from oolong tea -- they may experience insomnia, irritability, heart palpitations or dizziness. Both dopamine and norepinephrine enhance overall brain function, as well as mood and the ability to focus (Second, research has shown that theanine, an amino acid in oolong tea, may help reduce Additionally, the rich polyphenol content of oolong tea protects brain and nerve cells from oxidative damage (Tea, including oolong, may have a role in cancer prevention. Oolong tea and black tea are both types of tea known as true teas — that means they are made from the leaves of the tea plant known as the Camellia sinensis plant. However, excessive doses, like 7-10 cups daily, are harmful. One study of patients with eczema found that those who drank a large amount of tea each day in addition to continuing their regular treatment had an improvement of symptoms after just one month (Despite providing a laundry list of health benefits, oolong tea extract certainly isn’t perfect. The caffeine in oolong tea can increase how quickly your body gets rid of lithium. Poor sleep. The difference lies in how long the leaves ferment. Taking oolong tea along with verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of caffeine side effects including jitteriness, headache, and an increased heartbeat.The body breaks down the caffeine in oolong tea to get rid of it. Some medications used for depression can also stimulate the body. Taking oolong tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. #9. Do not take caffeine-containing products and ephedrine at the same time.Oolong tea contains caffeine. Oolong tea reduces the body's osmotic calcium levels, which is essential for bone growth. Moreover, those who suffer from severe anxiety may want to avoid consuming oolong tea, as the caffeine can also cause one to overreact to situations of high stress (It is best to take 500 mg (scant 1/4 tsp) 1-2 times daily, or as otherwise suggested by a doctor. The body breaks down caffeine to get rid of it. Fermentation, or its lack, gives teas their color and aroma. In fact, a particular Oolong tea is said to have anti-hyperglycemic properties since they contain polyphenols (kind of antioxidant having polyphenolic substructure) that work towards reducing blood sugar and keeping insulin levels in check.A certain study was conducted on about 20 patients taking hyperglycemic medications. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.WebMD does not provide medical advice, diagnosis or treatment.This survey is being conducted by the WebMD marketing sciences department.All information will be used in a manner consistent with the WebMD There are several possible oolong tea benefits including weight loss, anti-cancer, and anti-diabetes.