": 17

Finasteride for BPH
The most common adverse sexual effects of finasteride for BPH are: trouble getting or keeping an erection, decrease in sex drive, decreased volume of ejaculate and ejaculation disorders. : 16 A 2010 Cochrane review found that men taking finasteride for BPH (with a mean age of 62.4) are at increased risk for impotence, erectile dysfunction, decreased libido, and ejaculation disorder for the first year of treatment. The rates became indistinguishable from placebo after 2–4 years and these side effects usually got better over time. Long-term
Finasteride may cause persistent adverse sexual, neurological and physical effects in a subset of men. A 2019 metastudy surveyed the literature on the reversibility of finasterides side effects. It identified three studies which demonstrated full reversibility of side effects and eleven that describe patients with irreversible adverse events. The findings were most convincing in a retrospective review of about 12,000 patients that 1.4% of the cohort developed persistent ED (ED lasting longer than 90 days post-withdrawal). Post-finasteride syndrome
Men in the U.S. and Canada concerned about persistent sexual side effects "coined the phrase post-finasteride syndrome, which they say is characterized by sexual, neurological, hormonal and psychological side effects that can persist in men who have taken finasteride for hair loss or an enlarged prostate". As of 2016, Merck was a defendant in approximately 1,370 product liability lawsuits which had been filed by customers alleging they have experienced persistent sexual side effects following cessation of treatment with finasteride.A 2019 editorial in The BMJ called post finasteride syndrome "ill defined and controversial".
Causes
Common causes include infection, or reaction to medication such as an analgesic, anti-inflammatory, or antibiotics such as methicillin (meticillin). Reaction to medications causes 71% to 92% of cases. Drugs
This disease is also caused by other diseases and toxins that damage the kidney. Both acute and chronic tubulointerstitial nephritis can be caused by a bacterial infection in the kidneys known as pyelonephritis, but the most common cause is by an adverse reaction to a medication. The medications that are known to cause this sort of reaction are β-lactam antibiotics such as penicillin
and cephalexin, and nonsteroidal anti-inflammatory drugs (aspirin less frequently than others), as well as proton-pump inhibitors, rifampicin, sulfa medications, fluoroquinolones, diuretics, allopurinol, mesalamine, and phenytoin. The time between exposure to the drug and the development of acute tubulointerstitial nephritis can be anywhere from 5 days to 5 months (fenoprofen-induced). Diagnosis
The condition can appear without symptoms. When present they may appear widely varied and can occur rapidly or gradually.When caused by an allergic reaction, the symptoms of acute tubulointerstitial nephritis are fever (27% of patients), rash (15% of patients), and enlarged kidneys. Some people experience dysuria, and lower back pain. In chronic tubulointerstitial nephritis the patient can experience symptoms such as nausea, vomiting, fatigue, and weight loss. Other conditions that may develop include a high concentration of potassium in the blood, metabolic acidosis, and kidney failure. Blood tests
About 23% of patients have a high level of eosinophils in the blood. Urinary findings
Urinary findings include:

Eosinophiluria: Original studies with Methicillin-induced AIN showed sensitivity of 67% and specificity of 83%.