Kopplungsdose

Kopplungsdose is a pharmacological concept used primarily in the practice of psychopharmacology and endocrinology to maintain therapeutic drug levels while transitioning a patient from one medication to another. The term, which translates literally as “coupling dose,” refers to the initial dose of the new drug given such that its plasma concentration optimally overlaps with the waning concentration of the medication being discontinued. This overlap protects the patient from gaps in drug coverage that could lead to relapse of symptoms, withdrawal phenomena, or rebound effects that might otherwise occur during the transition.

In routine practice, the Kopplungsdose is calculated either by prescribing the same therapeutic dose of the new agent as that of the discontinued drug or by adjusting for pharmacokinetic differences. For example, when switching from one selective serotonin reuptake inhibitor (SSRI) to another, the new SSRI may be started at the same dosage as the prior SSRI, while the old drug is tapered. In endocrine therapy, Kopplungsdosen are used during the switch from one hormone replacement formulation to another to preserve stable hormone levels. The duration of overlap typically lasts from one to several dosing intervals, allowing for clearance of the preceding drug while achieving steady-state concentrations of the new one.

Guidelines from national psychiatric societies and pharmacological review articles provide recommendations on the practical application of Kopplungsdosen, including considerations of drug half-lives, metabolism pathways, and patient-specific factors such as liver function and concurrent medications. While the approach is generally accepted, some clinicians question its necessity, especially when the pharmacokinetic profiles of the drugs involved are markedly different. In such cases, alternative strategies such as rapid tapering or extended overlap periods are considered to avoid pharmacodynamic conflicts and minimize adverse effects.