Astemizole
Astemizole (marketed under the brand name Hismanal, developmental code R43512) was a second-generation antihistamine drug that has a long duration of action. Astemizole was discovered by Janssen Pharmaceutica in 1977. It has been withdrawn from the market in most countries because of rare but potentially fatal side effects (QTc interval prolongation and related arrhythmias due to hERG channel blockade).
Allylestrenol
Side effects of allylestrenol are few and have not been well-defined, but are assumed to be similar to those of related medications (i.e., other progestins). When used at high dosages in the treatment of BPH in men, allylestrenol can cause symptoms of hypogonadism and sexual dysfunction. The medication indeloxazine may be able to counteract allylestrenol-associated sexual dysfunction. Allylestrenol has no androgenic or other off-target hormonal side effects.