Found a bit more info about dosage...
"Treatment protocols may involve continuous spironolactone use at 50mg to 200mg per day or cyclic use. For example 50mg or 100mg twice daily from the 4th to the 22nd day of the menstrual cycle. Numerous treatment protocols involving spironolactone have been used in different studies, but no particular treatment approach has been shown to be significantly superior. Combination therapy with an oral contraceptive pill or dexamethasone appears to have an improved beneficial effect on hirsutism and limits side effects.
Spironoolactone is a diuretic, so it's advised to drink plenty of water while taking it. Side effects with spironolactone are generally transient. As with all antiandrogens , spironolactone use should be avoided during pregnancy and in women who have a family history of breast cancer, although there is no proven association between spironolactone and breast malignancy."
"iii) Spironolactone (Aldactone®) was originally marketed as a diuretic, but has limited uses in that field. Its efficacy as an antiandrogen was noticed through its ability to decrease testosterone production, increases the rate of testosterone metabolism, to inhibit dihydrotestosterone binding to the androgen receptor and to retard the conversion of testosterone to dihydrotestosterone by its effect on 5 a - reductase. Spironolactone is a stronger antiandrogen than cyproterone, but also has progestational effects. The dosage is 50 - 100 mg. by mouth twice a day. Cyproterone acetate is taken up in adipose tissue and then slowly released, thus rendering the patient susceptible to menstrual irregularity. A reversed sequential regimen was developed to avoid this side effect. It consists of giving cyproterone acetate on days 5 though 15 of the cycle in doses initially of 50 to 100 mg. per day. Ethynyl estradiol is given in a dose of 50 µg daily from days 5 through 26 of the cycle. Dose reduction is possible once effective remission of hirsutism occurs. A combination oral contraceptive (Diane) containing cyproterone acetate (2 mg.) and estrogen ethinyuloestradiol (50 µg) is sometimes used for maintenance. Side effects include nausea, fatigue, irregular menses, and headache. Because of its previous use as a diuretic, high serum potassium and low blood pressure have been postulated, but do not occur in practice. Spironolactone like cyproterone interrupts the masculinization of a male fetus so contraception should be practiced by a woman previously infertile with polycystic ovarian disease as ovulation has been induced with spironolactone."
"Female Hirsutism 100mg to 200mg daily in divided doses is usual however 50mg daily has also been shown to be effective.
Clinical improvement is usually shown within 3 to 6 months and an initial course of treatment should continue for 12 months.
ALDACTONE may be administered continuously or as a cyclical dosage for approximately three weeks out of every four. Dosing from day 5 to 21 of the menstrual cycle, with a drug free interval during menstruation has been effective.
Cyclical dosing may reduce menstrual irregularities in women with previously regular cycles.
Combined use with oestrogen-progestogen oral contraceptives may also be considered to provide both regular menstrual cycles and adequate contraception."
That's a long way of saying I think your doctor is right - but maybe in the future you'll be able to lower your dosage.
I would suggest (and I'm sure Tanya will agree) that you go back to your doc after a week or so and get your potassium level checked.