Bupivacaine should be used with caution in patients receiving other local anesthetics or pharmaceuticals structurally similar to amide-type local anesthetics, e.g. certain antiarrhythmics, such as lidocaine and mexiletine since the systemic toxic effects are additive. Specific interaction studies with bupivacaine and anti-arrhythmic drugs class II (e.g. amiodarone) have not been performed, but caution should be advised.