Phenothiazines, like chlorpromazine, are used to treat___________. Psychosis A1 Blockers have __________ as an adverse effect. Hypotension (They work too well) Which drug works on the hypothalamus to reduce fevers? acetaminophen (Tylenol) Which drugs work to reduce symptoms of BPH? A1 Blockers such as tamsulosin (Flomax) and 5-Alpha Reductase Inhibitors such as Proscar.