Some of the side effects associated with Novocaine, a local anesthetic typically used during dental procedures, include head pain and chills, notes WebMD. Less common side effects include nausea, dizziness, vomiting, drowsiness and blurred vision. Recipients of the drug may also experience confusion and anxiety.
Additional uncommon side effects of Novocaine include allergic reactions, abnormal heart rhythms, depressed heart function, hives and seizures, notes WebMD. Other side effects include asthma attacks, blood vessel dilation, ringing in the ears, water retention and twitching. Another rare side effect of the drug is methemoglobinemia, a condition in which excessive methemoglobin, a form of hemoglobin, is produced by the body.
Side effects of Novocaine that involve both cardiovascular and central nervous systems are often the result of elevated plasma levels, explains Dr. Elmira Gadol. Excessive plasma levels are, in turn, caused by accidental intravascular injections, abnormally high dosages or speedy absorption. Unsuitable usage or doses may lead to low blood pressure and an inability to breathe. A small fraction of side effects are due to excessive sensitivity to the drug or inability to tolerate normal doses.
Novocaine is contraindicated for medications used to treat high blood pressure, states Drugs.com. Other drugs that should not be used with Novocaine include warfarin, an anticoagulant used for preventing strokes and blood clots and guanadrel, a drug used to treat hypertension.