Does the natural product ""Oleum Strophantus Forte"" contain any substance similar to glucoside. A

Fråga: "Does the natural product "Oleum Strophantus Forte" contain any substance similar to glucoside. And if so how much? Can that amount affect the heart frequency? Is there any risk of interaction with Seloken (metoprolol)? Background: A 70-year old male patient with angina pectoris. His current therapy includes: T Trombyl (acetylsalicylic acid) 75 mg 1x1, T Nitromex (nitroglycerine) 0.5 mg as required, T Zantac (ranitidine) 20 mg 1x2 and a health product Oleum Strophanti Forte 125 mg capsules, 2 x2. Recently he was also put on metoprolol 50 mg 1x1."

Sammanfattning: Oleum Strophantus Forte contains k-strophantin, a compound with similar pharmacological properties as digitalis. Metoprolol and k-strophantin can have additive effects leading to bradycardia although clinical documentation is scarce.

Svar: According to the package leaflet, each capsule of Oleum Strophantus Forte contains Oleum Strophanthi Kombe 125 mg (1). The extract of Strophantus kombe contains an active substance, k-strophanthin which has pharmacological properties similar to that of digitalis (2). K-strophantin is found also in the roots and the aerial parts of the Lily-of-the-valley, Covallari Majalis L which grows in Sweden (1). Although the amount of strophantin contained in the capsule is not mentioned in the leaflet, one should expect similar effect on the heart frequency as that observed after digoxin administration.

Metoprolol in combination with digoxin can have additive effective with decreased sinoatrial (SA) or atrioventricular (AV) conjunction or automation leading to cardiac block (3). Similar effects can be expected if Oleum Strophantus Forte is taken concomitantly with metoprolol.