Topical Diazoxide

We take the 30 mg you apply each day and assume a share is absorbed through the scalp (the range you pick). Absorbed diazoxide clears slowly, with a half-life of about a day or more, so daily use builds up over the first week or two and then holds steady. That plateau is what the chart shows.¹

At steady state, the average blood level equals the daily absorbed dose divided by how fast the body clears it. Using clearance measured in adults, 10% absorption works out to about 541 ng/mL, and the other ranges scale in proportion. Clearance varies from person to person, so an individual could sit at roughly 0.6 to 1.5 times these figures.¹

Where effects may begin: blood pressure may start to respond at around 10,000 ng/mL.² No study has measured the blood level where blood sugar starts to rise in adults, so we work it out from dosing. The smallest oral doses shown to nudge blood sugar, about 2 mg/kg a day or a single 6 mg/kg dose, come to roughly 10,000 ng/mL and up with the same clearance figures and published single-dose peaks.^1,2,3 We draw the line at 10,000 ng/mL, the low end of that range. For context, people who take oral diazoxide on purpose to raise their blood sugar run about 15,000 to 50,000 ng/mL,⁴ and high blood sugar has been linked to levels above 100,000 ng/mL.⁵ These are modeled estimates, not measured blood levels.

1. Ogilvie RI, Nadeau JH, Sitar DS. Diazoxide concentration-response relation in hypertension. Hypertension 1982;4(1):167-173. PubMed (opens in a new tab). Also: PROGLYCEM prescribing information, FDA label (opens in a new tab).
2. AHFS Drug Information, Diazoxide: minimum blood concentrations of about 10 mcg/mL (10,000 ng/mL) for initial blood-pressure effects; peak blood concentrations after a single 10 mg/kg oral dose. Monograph (opens in a new tab). Also: Monograph (oral) (opens in a new tab).
3. Schreuder T, et al. Diazoxide-mediated insulin suppression in obese men: a dose-response study. Diabetes Obes Metab 2005;7(3):239-245. Due A, et al. No effect of inhibition of insulin secretion by diazoxide on weight loss in hyperinsulinaemic obese subjects during an 8-week weight-loss diet. Diabetes Obes Metab 2007;9(4):566-574. Ramanathan RP, Arbeláez AM, Cryer PE. Partial inhibition of insulin secretion results in glucose intolerance but not hyperglucagonemia. Diabetes 2011;60(4):1324-1328. Schreuder 2005 (opens in a new tab). Also: Due 2007 (opens in a new tab). Also: Ramanathan 2011 (opens in a new tab).
4. Pruitt AW, Dayton PG, Patterson JH. Disposition of diazoxide in children. Clin Pharmacol Ther 1973;14(1):73-82. PubMed (opens in a new tab).
5. Kizu R, et al. Population pharmacokinetics of diazoxide in children with hyperinsulinemic hypoglycemia. Horm Res Paediatr 2017;88(5):316-323. PMC (opens in a new tab).