Diazoxide is a potent and rarely anti-hypertensive agent, nondiuretic benzothiazide;
it has diverse pharmacologic effects such as:
- Hypertrichosis (hair growth)
- Hyperglycemia (increase blood sugar) associated
with associated with suppression of insulin release, which is why it
is used to treat hypoglycemia
- Increase of serum levels of androgens.
The hypertrichotic effect of the application of topical diazoxide was examined
by several authors to take advantage of the side effect to treat pattern baldness. In 1989, a topical formulation of diazoxide was reported to show
efficacy in treating male pattern baldness. A study made with 19 male subjects
with “early to mid-stage” pattern baldness treated with
3% diazoxide solution twice daily for 2 to 11 months showed four men had
dense growth by way of some new terminal veins, one had vellus hair growth,
and seven had no re-growth at all. Moreover, one patient developed local
Phosphodiesterase (PDE), an enzyme that catalyzes the hydrolysis of phosphodiester
bonds, is inhibited by diazoxide. This inhibiting action of diazoxide is
believed to be the potential mechanism of action of the compound in hair
growth. Moreover, PDEs cause the degradation of the cyclic nucleotides cAMP
and cGMP. PDEs are therefore important regulators of signal transduction
mediated by these molecules. In all probability, energy production is hindered
by dihydrotestosterone by keeping phosphodiesterase relatively inactive
and by suppressing various protein (enzyme) syntheses. Growing hair follicles
at premature stages are terminated by relatively high concentration of cAMP,
and repetition of such process over several years presumably transforms
terminal follicles to vellus type follicles and ultimately causes baldness.
This theory on the metamorphosis of terminal hair to vellus hair, however,
is not yet proven.
As researchers studied hair growth, they provided correlative evidence
that the opening of potassium channel is an important regulatory mechanism
for hair growth. Diazoxide, like Minoxidil, has been shown to be a potassium
channel opener. Although with far less frequency, oral diazoxide can induce
hypertrichosis in a distribution similar to that caused by oral minoxidil.