Trimethaphan / Arfonad (brief use as IV infusion only, in OR / ICU)

Question 1

Drug Class

Answer 1

Pharm: Ganglionic transmission blocker
Therapeutic: Antihypertensive

Question 2

Pharmacodynamics

Answer 2

Blocks nicotinic transmission within both sympathetic and parasympathetic ganglia (by blocking Nn receptors); produces veno and vaso dilation

Question 3

Pharmacokinetics

Answer 3

Useful only when given IV, produces fall in BP within minutes, partly metabolized and partly excreted by kidneys

Question 4

Toxicity

Answer 4

watch out for sudden severe drop in BP; also fall in HR; also reduction in just about any sympathetic or parasympathetic response

Question 5

Interactions

Answer 5

Additive effects with most other anti-hypertensives

Question 6

Special Considerations

Answer 6

Patients are quite miserable, hence only used during general anesthesia; also helps to tilt patients to help control BP

Question 7

Indications and Dose / Route

Answer 7

Given by IV infusion, and only to treat HTN crisis, or for controlled hypotension during cardiovascular surgery

Question 8

Monitor

Answer 8

Minute to minute monitoring of BP and HR

Question 9

Notes:

Answer 9

This is an example of the mechanism -> not used long term for HTN