Minoxidil Group Research Articles

Development of hypertension in animals with reduced total peripheral resistance.

The object of the present study was to determine whether deoxycorticosterone acetate (DOCA)-salt hypertension can be produced in rats in the presence of low total peripheral resistance (TPR) induced by long-term administration of minoxidil, a vasodilator. The rats were divided into four groups: sham-control, DOCA-salt, minoxidil, and DOCA-salt with minoxidil. The rats in both DOCA groups had DOCA pellets implanted subcutaneously and were given saline to drink. The rats in both minoxidil groups were given minoxidil (3 mg/day) in the drinking water throughout the experiment. Final measurements, including mean arterial blood pressure, cardiac index, and renal blood flow were made after 4-6 weeks. Flow measurements were made using radioactive microspheres. Cardiac index (ml.min-1.100 g-1) in sham-control rats averaged 18 +/- 2 and was higher in the other groups: 23 +/- 4 (DOCA-salt), 25 +/- 2 (minoxidil), and 30 +/- 2 (DOCA-salt plus minoxidil). Mean arterial pressure (mm Hg) was increased in both DOCA-salt rats (160 +/- 8) and DOCA-salt plus minoxidil rats (153 +/- 5) as compared with sham-control (116 +/- 2) and minoxidil (113 +/- 3) rats. There was no significant difference in TPR between the sham-control and DOCA-salt rats, but TPR in minoxidil and DOCA-salt plus minoxidil rats was 30% and 28% lower than that in untreated sham-control and DOCA-salt hypertensive rats, respectively. In contrast, renal vascular resistance was significantly increased in both DOCA-salt groups as compared with non-DOCA-salt groups.(ABSTRACT TRUNCATED AT 250 WORDS)

TREATMENT OF FEMALE ANDROGENETIC ALOPECIA WITH MINOXIDIL 2%

The safety and efficacy of minoxidil 2% for the treatment of female androgenetic alopecia was assessed in a 32-week double-blind placebo-controlled trial. Thirty-three women aged 22 to 44 years with hair loss classified as Ludwig's grade I or II were enrolled, and 28 completed the trial. Before the administration of treatment, mean nonvellus hair counts were taken within a 1-cm2 target area of the scalp. For the 15 patients in the minoxidil group, the mean count was 169 hairs compared with 161 hairs for the 13 patients in the placebo group. At the completion of the trial, the patients treated with minoxidil 2% had a mean nonvellus hair count of 195 hairs versus a mean hair count of 177 for patients in the placebo group; 60% (9) of the patients in the minoxidil group showed minimal to moderate hair growth compared with 46% (6) of the patients in the placebo group. No serious side effects were encountered during this study, nor any significant changes in safety parameters. There were no dropouts due to medical events related to minoxidil 2%.

Quinapril, an angiotensin converting enzyme inhibitor, prevents cardiac hypertrophy during episodic hypertension.

Six control dogs, six dogs treated with 1.5 mg/kg b.i.d. quinapril, and six dogs treated with 8 mg/kg q.d. minoxidil underwent 6 hours daily of hindquarter compression for 9 weeks. Minoxidil significantly decreased baseline blood pressure (-17 mm Hg; p less than or equal to 0.01), whereas quinapril decreased baseline blood pressure 11 mm Hg but not significantly (p = 0.15). Hindquarter compression elicited blood pressure increases in all three groups (control +18, quinapril +13, minoxidil +19 mm Hg). After 9 weeks, left ventricular mass in control dogs increased 22% (p less than 0.004); a similar increase was seen in minoxidil-treated dogs (+22%, p less than 0.0001) but not in the quinapril-treated group (+4%, p less than 0.15). The increase in left ventricular mass in control dogs was concentric (increased epicardial volume only), whereas in the minoxidil group, the hypertrophy was eccentric (both epicardial and endocardial volumes increased). The minimal hypertrophy in the quinapril group was concentric (no change in epicardial, but a decrease in endocardial volume). Quinapril had little hypotensive effect, but prevented the development of left ventricular hypertrophy, whereas minoxidil did not prevent hypertrophy in spite of its hypotensive effect. The mechanism of this differential effect of direct vasodilation versus converting enzyme inhibition on left ventricular hypertrophy is not fully elucidated. The results with quinapril suggest that some antihypertensive agents may positively affect left ventricular hypertrophy in spite of the absence of a large effect on baseline blood pressure or on blood pressure reactivity.

AUSTRALIAN TRIAL OF TOPICAL MINOXIDIL AND PLACEBO IN EARLY MALE PATTERN BALDNESS

One hundred and sixty nine men with early male pattern baldness (androgenic alopecia) were treated in a random, double-blind fashion with either 2% minoxidil solution or placebo vehicle for 24 weeks, one ml applied twice daily. After 24 weeks all patients received the active solution until week 48. After 24 weeks the minoxidil treated patients had increased their non-vellus hair counts significantly more than the placebo treated group; means were 37.6 and 8.8 hairs per reference area, 95% C.I. for difference = 10.85 to 60.75. The rate of non-vellus hair regrowth was also greater among minoxidil treated patients than placebo treated patients. Nine (12.5%) evaluable minoxidil treated patients compared with 2 (2.7%) evaluable placebo treated patients reported moderate or dense hair regrowth at week 24. Minimal regrowth was reported by 18 (25%) active group and 15 (20%) placebo group patients. The investigators considered that 3 (2%) of the minoxidil group and none of the placebo group had moderate hair regrowth and that none had dense regrowth. After 48 weeks treatment 28 (23%) patients considered that they had moderate hair regrowth and the investigators considered that 14 (12%) patients had moderate regrowth. None had dense growth. No serious adverse reactions or deaths were reported. Minoxidil solution appeared to be an efficacious and safe treatment for early androgenic alopecia.

Arterial vasodilators, cardiac volume load, and cardiac hypertrophy in normotensive rats

To assess a possible involvement of cardiac volume overload in the development of cardiac hypertrophy during chronic arterial vasodilator treatment, changes in indexes of cardiac volume load in relation to changes in cardiac anatomy were evaluated during treatment of normotensive rats with 120 mg/l hydralazine or 120 mg/l minoxidil, with drinking water. Long-term treatment with hydralazine, but not minoxidil, caused small decreases in systolic blood pressure; neither vasodilator affected heart rate with chronic treatment. Arterial vasodilator treatment for 2 wk or more resulted in increases in plasma and blood volumes by 10-20%. Both arterial vasodilators increased right atrial pressure and left ventricular end-diastolic pressure in the initial weeks of treatment. Only the minoxidil group showed a persistent increase in right atrial pressure throughout the treatment period. These hemodynamic changes were associated with increases in left ventricular (LV) internal diameter and right ventricular (RV) weight, and with minoxidil these changes were also associated with increased LV weight. LV wall thickness did not increase. Cardiac volume overload therefore indeed occurs during treatment with arterial vasodilators and may contribute to their effects on cardiac anatomy (i.e., development of RV hypertrophy and, in the case of minoxidil, also, eccentric LV hypertrophy), which are consistent with cardiac volume overload.

Chronic angiotensin converting enzyme inhibition in the two-kidney, one clip hypertensive rat.

Treatment with an angiotensin converting enzyme (ACE) inhibitor in renovascular hypertension produces acute effects on renal function; however, the long-term consequences of this are not known. We have studied the effect of chronic enalapril treatment on renal structure and function in the two-kidney, one clip model of renovascular hypertension in the rat. Four weeks after the left renal artery was clipped, the hypertensive rats were randomly allocated to treatment with enalapril, minoxidil or to no treatment. The drug dose was titrated for maximal hypotensive effect. After 4 months of treatment blood pressures were 129 +/- 3 mmHg (enalapril), 193 +/- 5 mmHg (minoxidil) and 220 +/- 4.8 mmHg (no treatment). Twelve months later survival was 84% (enalapril group), 48% (minoxidil group) and 15% (untreated group). Split kidney function (51Cr-EDTA clearance, ml/min) of the clipped kidneys was 0.0 (enalapril group), 0.26 +/- 0.23 (minoxidil group) and 0.74 +/- 0.13 (untreated group). The clipped kidney from enalapril-treated rats weighed 0.46 +/- 0.1 g, much less than in the minoxidil-treated group (1.2 +/- 0.07) or the untreated group (1.14 +/- 0.10). Enalapril treatment was withdrawn for 2 weeks in five rats, but the clipped kidney remained small and non-functional. Histological examination revealed marked interstitial fibrosis and tubular atrophy in clipped kidneys from both enalapril groups, in contrast to minor changes in the minoxidil-treated and the untreated groups. We conclude that chronic enalapril treatment of two-kidney, one clip hypertension in the rat improved survival and preserved total renal function, but was associated with irreversible fibrotic atrophy of the clipped kidney.

Topical 2% Minoxidil Solution in Male Pattern Alopecia. The Initial European Experience

ABSTRACT: A double‐blind, 48‐week study was conducted to evaluate the safety and efficacy of topically applied 2% minoxidil solution in the treatment of male pattern baldness. Patients were randomly assigned to receive either 2% minoxidil solution or placebo for the first 24 weeks. After week 24, the placebo patients were crossed over to treatment with 2% minoxidil solution. Of the 428 patients enrolled in the study, 384 were evaluable at the end of the placebo‐controlled period, and 329 were evaluable at the end of the study. At the end of the placebo‐controlled period, the mean nonvellus hair count in the 2% minoxidil group was significantly higher than in the placebo group (p= 0.0187). The mean increase in nonvellus hair in the 2% minoxidil group from baseline to week 24 was also significantly higher than in the placebo group (p= 0.0385). From weeks 24 to 48, when both groups were on active drug, there was a statistically significant increase in the nonvellus hair count for both groups using within‐group analysis. The analysis of the patients'and investigators'assessment of hair growth showed significant differences in the distribution of responses between treatments at week 24. In both cases, it was believed that more hair growth

Psychological Characteristics of Men With Alopecia Androgenetica and Effects of Treatment With Topical Minoxidil An Exploratory Study

ABSTRACT: Psychological characteristics were studied in 85 healthy men with early‐stage alopecia androgenetica who participated in a double‐blind clinical trial on the effect of minoxidil. No evidence of psychosocial malfunctioning was found in the group suffering from hair loss as indicated by personality traits, general psychological adjustment and social functioning. These subjects were less rigid and more self‐confident than comparable norm groups. However, specific problems attributed to hair loss were present in more than 30%. More psychological improvement, with regard to hair problems, social discomfort, and self‐esteem occurred in the minoxidil group than in the placebo group. The findings are exploratory, because the pretest data were obtained in retrospect.

Topical Minoxidil in Androgenetic Alopecia Scandinavian and Middle East Experience

ABSTRACT: A 24‐week, double‐blind, placebo‐controlled study was conducted in Denmark, Egypt, Jordan, Norway, and Sweden to compare the efficacy and safety of topically applied 2% minoxidil solution with those of placebo in the treatment of early male pattern baldness. One hundred fifty‐one men were evaluable at week 24. They applied 1 ml of either the placebo or 2% minoxidil solution twice daily for the duration of the study. The 2% minoxidil group demonstrated superiority to placebo in all primary efficacy parameters evaluated, ie, nonvellus hair counts at week 24, change in non‐vellus hair counts from baseline to week 24, and patient and investigator assessment of hair regrowth at week 24. In addition, 2% minoxidil was found to be superior to placebo in decreasing the diameter of the bald scalp from baseline to week 24. No differences in systolic and diastolic blood pressures, pulse rate, or body weight were considered to be related to the minoxidil. One patient discontinued the study when he developed folliculitis after 2 weeks of minoxidil administration. Two percent minoxidil solution is a safe and effective treatment for early male pattern baldness.

Use of topical minoxidil in the treatment of male pattern baldness

This 12-month, double-blind, randomized study evaluated the safety and efficacy of topical minoxidil in the treatment of male pattern baldness. Three formulations were compared: 2% minoxidil solution, 3% minoxidil solution, and placebo. After 4 months all placebo patients crossed over to treatment with the 3% solution. Of the 96 patients randomized into the study, 79 were evaluable at month 12; 25 of these were in the 2% minoxidil group, 24 were in the 3% minoxidil group, and 29 were in the placebo-to-3% solution switchover group. At monthly intervals a hair count was obtained within a 1-inch diameter area on the scalp vertex. In addition, a gross visual estimate of the degree of new hair growth over the entire balding area was made independently by the investigator and the patient. At the end of 4 months there was significant regrowth of nonvellus (terminal and indeterminate) hairs in the patients using the 2% and 3% solutions (p = 0.0001). The mean nonvellus hair count at month 4 was 162.8 in the 2% minoxidil group, 155.4 in the 3% minoxidil group, and 107.1 in the placebo group. The mean increase in the 2% and 3% treatment groups was 58.2 and 48.8, respectively, whereas the mean increase in the placebo group was 4.0. Total hair counts at month 4 demonstrated significantly more growth of hair in the 2% minoxidil group than in the placebo group (p = 0.013), with no significant difference between the 3% minoxidil group and the other two treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical minoxidil in early androgenetic alopecia

A randomized, double-blind trial was conducted to determine the relative efficacy and safety of topical minoxidil solution for progressive male pattern baldness. One hundred fifty men with a discernible vertex balding spot were randomly assigned to treatment with either 2% topical minoxidil, 3% topical minoxidil, or placebo. After 4 months, patients receiving placebo were crossed over to 3% minoxidil. The study was concluded after 12 months of treatment, at which time 100 subjects were evaluable. Efficacy was determined primarily by objective hair counts at monthly intervals and by subjective patient evaluations at 4 and 12 months. Patients applying active medication had significantly greater growth of nonvellus hairs at 4 months than did their placebo counterparts (p = 0.0018 for 2% minoxidil vs placebo; p = 0.0167 for 3% minoxidil vs placebo). In patients crossed over from placebo to 3% minoxidil, the rate of growth of nonvellus hairs increased to fifteen hairs a month during the next 4 months and slowed to ten hairs a month during the last 4 months. Within-group analyses for month 12 evaluable patients demonstrated significant increases in total hair counts for all three groups (p less than or equal to 0.0001). According to investigator evaluations at month 12, 82% of the 2% minoxidil group, 78% of the 3% minoxidil group, and 83% of the placebo to 3% minoxidil group had new hair growth. Clinically insignificant minoxidil blood levels resulted from scalp absorption. Thirty-six medical events in twenty-six patients were deemed related to the study drug; twenty-seven of these events were dermatologic in nature, and all were mild and self-limiting.

Double-blind, placebo-controlled evaluation of topical minoxidil in extensive alopecia areata

The safety and efficacy of 3% topical minoxidil were evaluated in the treatment of extensive patchy alopecia areata, alopecia totalis, and alopecia universalis. Patients with extensive patchy alopecia areata had greater than 50% scalp hair loss. In this double-blind study, thirty subjects applied minoxidil or placebo to half of the afflicted scalp area twice daily, with overnight petrolatum occlusion, for 1 year. Both male and female subjects, ranging in age from 9 to 65 years, were enrolled, fifteen subjects to each treatment group. Minoxidil applications were generally well tolerated except for three instances of scalp itching and dermatitis, two of which necessitated discontinuing the medication. Hair growth was seen in seven of eleven evaluable subjects (63.6%) in the minoxidil group and in five of fourteen evaluable subjects (35.7%) in the placebo group. Excellent, cosmetically acceptable hair growth was seen in three of eleven minoxidil-treated subjects (27.3%) and in one of fourteen placebo-treated subjects (7.1%). Examination of vital signs and laboratory measurements revealed no evidence of systemic effects of minoxidil. Seven of the twelve subjects assayed in the minoxidil group had detectable minoxidil serum levels, ranging from 0.4 to 7.5 ng/ml.

Androgenetic alopecia: Treatment results with topical minoxidil

A double-blind 12-month trial was conducted to evaluate the safety and efficacy of topical minoxidil in patients with androgenetic alopecia. During the first 4 months of the study, patients applied a topical solution containing either 2% minoxidil, 3% minoxidil, or placebo to their scalps twice daily. At the end of the fourth month, patients taking placebo were crossed over to treatment with 3% minoxidil solution. Of 60 patients enrolled in the study, 43 were evaluable at month 12. Hairs were counted in a 1-inch target area and classified as vellus, indeterminate, and terminal; the latter two classifications were combined as nonvellus hairs for further statistical analysis. All three groups had significant increases in total, nonvellus, and terminal hair counts between baseline and month 4 and between month 4 and month 12. At month 4 the average total hair counts increased from a baseline mean of 158.2 to 270.2 in the 2% minoxidil group, from 156.6 to 287.0 in the 3% minoxidil group, and from 162.6 to 246.9 in the placebo group. At month 12 the means were 415.6, 448.5, and 471.1 in the 2% minoxidil, 3% minoxidil, and placebo-3% minoxidil crossover subjects, respectively. The increases from month 4 to month 12 were highly significant for each group (p = 0.0001). Average increases in nonvellus hair counts between months 4 and 12 were 216, 181, and 264 in the 2% minoxidil, 3% minoxidil, and placebo-to-3% minoxidil crossover groups, respectively, all highly significant differences from zero (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and efficacy of topical minoxidil in the management of androgenetic alopecia

Of 149 subjects with androgenetic alopecia, 102 completed 1 year of a double-blind, randomized study comparing 2% minoxidil and 3% minoxidil solutions for safety and efficacy. One third of the subjects used a vehicle placebo for the first 4 months and then switched to 3% minoxidil. At 12 months the 2% minoxidil group switched to a 3% solution. During months 5 to 12 a steady increase in terminal hair counts occurred to an equal degree within the 2% and 3% minoxidil groups and the 3% treatment group switched from placebo. Total hair counts at 12 months increased from a baseline mean of 63.5 to 180.6 in the 2% treatment group, from 61.0 to 179.9 in the 3% group, and from 65.0 to 191.1 in the placebo to 3% crossover group. Although all 102 subjects completing 12 months of the study thought that visible hair growth had resulted, 89 were considered by the investigators to have visible growth. Dense hair growth, defined as hair long enough to cut or comb, was present in 48 subjects by their own evaluation and in 33 subjects by investigator evaluation. There were no serious side effects. Two instances of allergic contact dermatitis and four of pruritus were attributed to use of the drug. Two individuals complained of impotence, which disappeared within a few days of discontinuation of topical minoxidil. This effect has not been reported during the use of minoxidil in its oral form (Loniten) for the treatment of hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-response study of topical minoxidil in male pattern alopecia

Fifty-eight men with Hamilton scale type III vertex or type IV male pattern baldness were studied to determine the dose-response activity of low concentrations of topical minoxidil in promoting hair growth. The patients were treated with topical minoxidil at doses of 0.01%, 0.1%, 1%, or 2% or placebo in a randomized double-blind design for 6 months. At the end of 6 months, patients using 0.1%, 1%, and 2% topical minoxidil solutions showed a significantly greater difference in the mean increase of nonvellus hair growth in comparison with those using 0.01% minoxidil or placebo. There was a clear dose-response correlation for the increase of nonvellus hairs in the 0.1%, 1%, and 2% minoxidil treatment groups. There was a statistically significant difference in patient's self-evaluation of overall hair growth and degree of decreased hair shedding in the 1% and 2% minoxidil groups when compared with the other study groups. From this study we conclude that significant increases in nonvellus hair counts occur with 0.1% and greater doses of minoxidil. However, only in patients treated with the 1% and 2% solutions of minoxidil was there clinically perceptible hair growth.

2% Topical Minoxidil Solution in Male-Pattern Baldness: Preliminary European Results

A 48-week, double-blind, randomized study was conducted in France, West Germany and the UK to compare the safety and efficacy of topical minoxidil 2% (Regaine; registered trade mark of the Upjohn Company) solution with placebo in the treatment of early male-pattern baldness. At week 24, the end of the placebo period, there were 225 evaluable patients, 116 in the treatment group and 109 in the placebo group. The 2% minoxidil group showed superiority to the placebo group with respect to the following parameters at week 24: (1) non-vellus hair counts (p = 0.0084); (2) changes in non-vellus hair counts compared with baseline values (p = 0.0227), and (3) investigators' evaluations of hair growth (p = 0.019). There was no significant difference between minoxidil and placebo treatment with regard to blood pressure, pulse or weight changes. No serious side effects were reported during the study. The greatest number of medical events were dermatological in nature and mainly local and mild in intensity. From week 24 to week 48 all patients received active medication and showed further hair growth. At week 48 the investigators evaluated the new hair growth as moderate or dense in 32.7% of the patients. Our conclusion confirms previous reported studies according to which topical minoxidil seems to offer a safe and efficacious treatment for early male-pattern baldness in some patients. Further studies need to be done to characterize the most likely responders.

Dose-response study of topical minoxidil in male pattern baldness

Eighty-nine healthy men with male pattern baldness completed a 6-month double-blind, placebo-controlled study of 0.01%, 0.1%, 1%, and 2% topical minoxidil. Subjects on 2% topical minoxidil had a statistically significant increase in mean total target area hair count over baseline compared to the placebo, 0.01%, and 0.1% topical minoxidil groups (p = 0.04). Changes from baseline were more impressive with the 2% topical minoxidil group but not significantly different from the 1% topical minoxidil group in all parameters of objective response to treatment. The investigator, however, rated more subjects as having at least a moderate cosmetic response to treatment in the 2% versus 1% topical minoxidil treatment group. These results indicate that 1% topical minoxidil is the lowest effective concentration of topical minoxidil for male pattern baldness of those tested. Because of the more impressive changes in hair counts and the cosmetic preference for the 2% versus 1% topical minoxidil, 2% topical minoxidil may be the standard preferred treatment for male pattern baldness.

Central and regional hemodynamic effects and neurohumoral consequences of minoxidil in severe congestive heart failure and comparison to hydralazine and nitroprusside

Minoxidil is a potent oral vasodilator of potential value in patients with congestive heart failure (CHF), although preliminary studies show that it causes fluid retention. To test whether minoxidil acts primarily as an arterial vasodilator in CHF, it was compared with hydralazine and nitroprusside. To evaluate its chronic efficacy and mechanism of fluid retention, the effects of minoxidil (7 patients) were compared, in a double-blind manner, with those of hydralazine (8 patients) on central and regional hemodynamics and the renin-angiotensin-aldosterone and sympathetic nervous systems. There was no demonstrable difference in the central hemodynamic effects of minoxidil and hydralazine in the dosages used. After 6 hours both drugs increased cardiac index (minoxidil group, from 1.65 ± 0.29 to 2.26 ± 0.40 liters /min/m 2, p < 0.0001; hydralazine group, from 1.88 ± 0.61 to 2.34 ± 0.90 liters/min/m 2, p < 0.0001), decreased systemic vascular resistance and increased heart rate without change in pulmonary arterial, pulmonary capillary wedge or right atrial pressures. Nitroprusside effects differed from those of minoxidil and hydralazine with respect to heart rate (p < 0.005) and mean pulmonary arterial (p < 0.007) and right atrial (p < 0.009) pressures. Nitroprusside also decreased relative hepatomesenteric flow compared with the other 2 agents (p < 0.005). Neither renal blood flow, glomerular filtration rate, filtration fraction, nor urinary sodium excretion were significantly altered acutely by any of the 3 drugs. Minoxidil and hydralazine did not differ in their neurohumoral effects: Both agents produced an increase in plasma norepinephrine concentration (p < 0.003) and plasma renin activity (p < 0.04), but no change in plasma epinephrine or aldosterone concentrations. After 1 week of double-blind therapy, fluid retention was a greater problem with minoxidil than with hydralazine. Thus, minoxidil behaves primarily as an arterial vasodilator in CHF, fluid retention is a severe adverse effect, and the greater degree of fluid retention with minoxidil than hydralazine is not attributable to differing acute effects on total renal blood flow or function, or differing effects on the renin-angiotensin-aldosterone or sympathetic nervous systems.

Double-Blind Comparison of Minoxidil and Hydrallazine in Severe Hypertension

1. Thirty moderately severely hypertensive patients were studied in a double-blind comparison of minoxidil and hydrallazine in combination with frusemide and propranolol. 2. Blood pressure control in both groups of patients was satisfactory but long-term control appeared to be better in the minoxidil group. 3. Renal function was well preserved in both groups. Evidence of cardiac hypertrophy was slow to resolve despite good control of blood pressure. Side effects were negligible, and patient acceptance and rehabilitation was excellent.