If an androgen-associated adverse reaction occurs, treatment should be interrupted and, after disappearance of the symptoms, be resumed at a lower dosage. Patients with latent or overt cardiac failure, renal dysfunction, hypertension, epilepsy or migraine (or a history of these conditions) should be monitored, since androgens may occasionally induce salt and fluid retention. Androgens should be used cautiously in pre-pubertal boys to avoid premature epiphyseal closure or precocious sexual development. A decrease in protein bound iodine (PBI) may occur,but this has no clinical significance. Treatment of male patients over the age of approximately 50 years with androgens should be preceded by a thorough examination of prostate and baseline measurement of prostate-specific antigen serum concentration.
The desired effects of mesterolone and its l7-esters according to this invention occur not only by injection but equally well in case of oral administration, which is preferred. The amount of effective agent in the thusformulated medicinal agents is 200 mg., preferably 1 50 mg., per day in a single or in divided doses. The above-mentioned dosage range is related to oral administration. Among the parenteral administrations the intramuscular administration is preferred. If a prolonged release is desired, the mesterolone is intramuscular administered as l7-Ester, ., as mesterolone cipionate, in a dosage range between 10 and 500 mg per 2 weeks, preferably in a dosage of 10 to 200 respectively 50 to 500 mg per two weeks, according to the desired effect.
Finasteride was the first 5-ARI to be introduced for medical use.  It was marketed for the treatment of BPH in 1992 and was subsequently approved for the treatment of pattern hair loss in 1997.  Epristeride was the second 5-ARI to be introduced and was marketed for the treatment of BPH in China in 2000.  Dutasteride was approved for the treatment of BPH in 2001 and was subsequently approved for pattern hair loss in South Korea in 2009 and in Japan in 2015.   The patent protection on finasteride and dutasteride has expired and both drugs are available as generic medications .