title: Heating and cooling of the nitroglycerin patch application area modify the plasma level of nitroglycerin.
abstract: 19 healthy volunteers wore a nitroglycerin patch releasing 10 mg per 24 h for 2 h. Subsequently, the skin area surrounding the patch was exposed to 15 min of local heating with an infrared bulb (Group A, n = 10), or local cooling with an ice-pack (Group B, n = 9). The patch was protected by an insulating shield (Styrofoam). After 10 min of heating, the median (Walsh) plasma nitroglycerin level increased from 3.1 to 7.6 nmol.l-1. Body temperature remained constant. After 15 min of cooling the median plasma level had dropped from 2.1 to 1.4 nmol.l-1. The results demonstrate that changes in skin temperature may cause extensive short-term changes in the bioavailability of nitroglycerin. Presumably, a subcutaneous or cutaneous reservoir builds up during transdermal treatment, and changes in regional cutaneous blood flow affect the rate of drainage from the reservoir into the systemic circulation.
authors.affiliation: Oslo University Hospital Ullevål, Department of Cardiology, Norway.
authors.forename: T O
authors.initials: TO
authors.lastname: Klemsdal
authors.forename: K
authors.initials: K
authors.lastname: Gjesdal
authors.forename: J E
authors.initials: JE
authors.lastname: Bredesen
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D003080:Cold Temperature; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D005996:Nitroglycerin / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood*; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply; D012881:Skin Temperature
chemical_list: D005996:Nitroglycerin