If you are currently being treated with any of the following medications, you should not use valerian without first talking to your healthcare provider.

Anesthesia
For those facing surgery, it is important to note that valerian may increase the effects of anesthesia and, thus, it is important to discuss the use of valerian with your healthcare providers (particularly the surgeon and anesthesiologist) well in advance of your planned operation. The doctors may advise you on how to taper use of valerian prior to the surgery. Or, they may allow you to continue use up to the time of surgery, making any necessary adjustments to the anesthesia and giving you medication to avoid possible withdrawal symptoms from the valerian while in the hospital.

Sedatives and Anti-anxiety Medications
There are no reports in the scientific literature to suggest that valerian interacts with any conventional medications. However, valerian is a sedative herb that may increase the effects of alcohol and medications for anxiety and insomnia. Valerian should not be combined with barbiturates (medications, such as pentobarbital, prescribed for sleep disorders or seizures), and should be used with caution, if at all, by people taking benzodiazepines (anti-anxiety and sleep inducing medications including alprazolam, diazepam, and lorazepam) or other sedative medications (such as antihistamines).