Can drugs with opposite mechanism of action be taken together?
Q: I am suffering from severe depression and anxiety. My previous doctor gave me Stablon 12.5(Tianeptine sodium salt) thrice a day for 6 months but I was not getting desirable response. Two days back I changed my Psychiatrist (of govt. hospital) and he prescribed me Venlor XR 37.5 Venlaxifine Hydrochloride twice a day by tapering stablon to twice a day. Now I am taking :- VenlorXR 37.5 BD, Stablon12.5 BD. Today while surfing I came to know that the mode of action of both the medicines are opposite, like Stablon is (NSRE) Norpinephrine Serotonin Reuptake Enhancer Venlor XR is (NSRI) Norpinephrine Serotonin Reuptake Inhibitor. Please guide me is it all right to take both the medicines at the same time.
A:You are right. Tianeptine (Stablon by Serdia) increases the reuptake (rather than inhibiting) of serotonin while venlafaxine (Venlor XR by Cipla) inhibits the reuptake. If given together they nullify each others effect. Hence they cannot be taken concurrently. In your case there should be no difficulty in starting on Venlor XR straightaway without tapering the dose of tianeptine. The problem with tianeptine, discovered in France, is that there is not much post-marketing experience with the efficacy and safety of this drug, since it is marketed in very few countries. For example the drug is not cleared by U.S. Food and Drug Administration or British Medicines and Healthcare products Authority or Therapeutic Goods Administration (TGA) of Australia.