Mercurial diuretics are a form of renal diuretic containing mercury. Although previously widely used, they have largely been superseded by safer diuretics such as thiazides, and are hardly used anymore.

History and mechanism

Inorganic

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

compounds, such as mercury(I)chloride ( calomel), were found to have diuretic properties when they were used to treat

syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, an ...

. Proposed use of these compounds date back at least to the 16th century, shortly after the beginning of the syphilis epidemic in 1497 following Columbus' return to Europe. Mercurial diuretics cause diuresis by reducing the reabsorption sodium in the ascending loop of Henle, thus causing more water being delivered to the distal convoluted tubule. Unfortunately, earlier physicians misconstrued hallmark symptoms of mercury poisoning such as excessive salivation as signs of mercury's efficacy, including up until the early 1960s when the use of mercurial diuretics was halted in medicine.

Side effects

Due to the idiosyncratic nature of mercury toxicity, the risk of severe disease and sudden death are unpredictable and frequently show no warning signs. Physicians during the 20th century believed that a fever/rash complex suggested the risk of severe side effects for the next upcoming doses if treatment was not halted. Warkany and Hubbard (1953) noted in their seminal paper establishing mercury as the cause of infantile acrodynia that "... in modern times the capricious behavior of mercurial diuretics has been rather disturbing to those who use them frequently. Thousands of injections are given without untoward effects but occasionally a therapeutic dose results in sudden death. Only rarely is this caused by the first dose. More often the patient tolerates several - in one case 164 - doses before the fatal reaction occurs. The mechanism of these reactions is not clear: they can neither be explained nor predicted; yet they cannot be denied." After finding associations between mercurial diuretics and "mercurial"

nephrotic syndrome Nephrotic syndrome is a collection of symptoms due to kidney damage. This includes protein in the urine, low blood albumin levels, high blood lipids, and significant swelling. Other symptoms may include weight gain, feeling tired, and foamy ...

, in addition to the sharp decline in infantile acrodynia cases after the late 1950s following the removal of many sources of childhood mercury exposure, the dangers of mercurial diuretics were realized. This led to the discontinuation of mercurial diuretics in favor of far less toxic and far more effective diuretics. This is similar to the fashion in which penicillin quickly replaced arsenic and mercury as the main antibiotic used in the treatment of syphilis for both children and adults.

Examples

Some common organic mercurials: *

Chlormerodrin Chlormerodrin is a mercurial diuretic commercially traded from 1952 until 1974 that was once used to treat patients with heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and s ...

* Merbaphen (Novasurol) *

Mersalyl acid Mersalyl (Mersal) is an organomercury compound and mercurial diuretic. It is only rarely used as a drug, having been superseded by diuretic medications that do not contain mercury and are therefore less toxic. It features a Hg(II) centre. Mersal ...

(Mersal, Salyrgan) *

Meralluride Meralluride is a mercurial diuretic. In a 1963 study done with rats, it was thought to act on the proximal tubules of the kidneys. Studies in the late 1970s showed the compound had antimicrobial effect against ''Proteus'' bacteria responsible fo ...

* Mercaptomerin *

Mercurophylline Mercurophylline is a mercurial diuretic Mercurial diuretics are a form of renal diuretic containing mercury. Although previously widely used, they have largely been superseded by safer diuretics such as thiazides, and are hardly used anymore. ...

* Merethoxylline procaine

History and mechanism

Side effects

Examples

References

See also