Directwerkende

Directwerkende is a Dutch adjective meaning directly acting. It is used to describe agents, mechanisms, or devices that exert their effect directly on the target without intermediate mediation. The term is common in Dutch-language pharmacology and engineering literature and is often contrasted with indirect or mediated action.

In pharmacology, directwerkende (direct-acting) agents interact with receptors or enzymes to produce a biological response without requiring the release or modification of endogenous mediators. For example, direct-acting adrenergic agonists bind directly to adrenergic receptors, producing a response on their own, whereas indirect-acting drugs increase the amount of neurotransmitter at the synapse to elicit a reaction. In vascular pharmacology, directwerkende vasodilators relax smooth muscle by acting on the vascular smooth muscle itself, as opposed to indirect-acting vasodilators that work by releasing endogenous mediators.

In engineering, the term describes devices or components that apply force or control directly on the element being actuated. A direct-acting valve or switch, for instance, translates the control input immediately into motion or actuation, without intermediate pilot or amplification pathways.

The meaning can vary between subfields, so context is important. In English-language texts, equivalents such as "direct-acting" are commonly used. The Dutch spelling often appears as "directwerkende," sometimes hyphenated as "direct-werkende."