nitric acid(redirected from HNO 3)
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pertaining to or containing nitrogen in one of its higher valences.
nitric acid a highly caustic, fuming acid that has a characteristic choking odor and can be fatal if swallowed. It is sometimes used as a cauterizing agent in the eradication of warts; large amounts of it on the skin can cause necrosis. It is also used in the form of its potassium and sodium salts. The antidote for nitric acid poisoning is liberal application of an alkali or sodium bicarbonate.
1. NO, a naturally occurring gas that in the body is a short-lived dilator released from vascular epithelial cells in response to the binding of vasodilators to endothelial cell receptors; it causes inhibition of muscular contraction, and thus relaxation. Excesses of nitric oxide are toxic to cells of the central nervous system and also cause the drop in blood pressure seen in septic shock. Called also endothelial- or endothelium-derived relaxing factor.
2. a preparation of nitric oxide used together with ventilatory support or other agents in the treatment of respiratory failure due to persistent fetal circulation in term and near-term neonates; administered by inhalation.
A strong acid oxidant and corrosive; HNO3.
nitric acid/ni·tric ac·id/ (ni´trik) a colorless liquid, HNO3, which fumes in moist air and has a characteristic choking odor; used as a cauterizing agent. Its potassium salt (potassium nitrate) is used in potassium deficiencies and as a diuretic; its sodium salt (sodium nitrate) as a reagent.
nitric acid (HNO3)
Etymology: Gk, nitron, soda; L, acidus, sour
a colorless, highly corrosive liquid that may give off suffocating brown fumes of nitrogen dioxide on exposure to air. Traces of nitric acid may be found in rainwater during a thunderstorm. Commercially prepared nitric acid is a powerful oxidizing agent used in photoengraving and metallurgy; in the manufacture of explosives, fertilizers, dyes, and drugs; and occasionally as a cauterizing agent for the removal of warts. Organic nitrates or polyol esters of nitric acid such as nitroglycerin and amyl nitrite are effective vasodilators often used in relieving angina, but exactly how they function in dilating arterial and venous smooth muscle is not yet understood. Historically known as aqua fortis.
ni·tric ac·id(nī'trik as'id)
A strong acid oxidant and corrosive.
nitric acid; HNO3 strong, self-limiting, oxidizing agent (see Table 1)
|Keratolytic/caustic agent||Indicated use|
|Whitfield's ointment (3% salicylic acid and 6% benzoic acid in white soft paraffin)||Treatment of mild tinea pedis|
|5% salicylic acid ointment||Applied daily for 7 days to soften hyperkeratosis and facilitate its removal|
|12% salicylic acid in collodion||Macerating agent; painted over callosity and left in situ for 7 days, to assist removal of heavy callosity|
|20-40% salicylic acid plaster||Applied topically and left in situ for 1-2 days to aid removal of corns|
|40-70% salicylic acid ointment||Applied topically in a cavitied pad and left in situ for 7 days for verruca treatment; the lesion should be masked|
|Calmurid cream (10% urea)||To hydrate anhidrotic skin; applied daily to treat dyskeratosis|
|40% urea cream||A strongly keratolytic agent, applied under an occlusive dressing and left in situ for 7 days, to soften, macerate and aid the reduction and removal of hypertrophied nails in patients who are unsuitable for nail avulsion|
|Monochloroacetic acid||A deeply penetrating caustic that is painful in use Applied, retained in situ and reviewed within 3-7 days, for the treatment of verrucae:|
1. as a saturated solution to the lesion
2. as a tiny crystal strapped over a masked lesion
3. as a tiny crystal embedded in 40-70% salicylic acid retained by a cavitied pad
|Trichloroacetic acid||A self-limiting caustic with a superficial action|
Applied directly to the verruca, after initial scalpel debridement of the lesion
May be used in conjunction with 75-95% silver nitrate (see below) as a diagnostic or a final treatment of verrucae
|75-95% Silver nitrate||A self-limiting caustic with a superficial action, causing a dark brown discoloration of the skin to which it is applied; it is used for the treatment of shallow or mosaic verrucae.|
Note: Some patients show an idiosyncratic local sensitivity or inflammatory reaction to applied silver nitrate
1. Applied directly to the lesion, after overlying callosity has been debrided off
2. Applied directly to the lesion in alternating layers with trichloroacetic acid
3. As a diagnostic aid to identify verrucous tissue; viral-infected skin cells show up as bright white dots within a few moments of the application of the layers of silver nitrate and trichloroacetic acid
|Potassium hydroxide (KOH)||A powerful keratolytic caustic with a great affinity for water that penetrates deeply dissolving precipitated protein; used to destroy soft tissues|
1. Overlying hyperkeratosis is debrided off the verruca and the foot is immersed in water for 5 minutes to hydrate the skin, then dried; a KOH pellet is rubbed into the lesion; the foot is reimmersed in water and the jelly-like material formed by the KOH on the lesion surface is debrided off. The process is repeated once or twice until the lesion appears to have gone, then glacial acetic acid is applied to neutralize the KOH
2. A similar protocol may be used to ablate nail matrix after removal of the overlying section of nail plate
3. KOH 5% liquid applied to heavy callosity and left in situ for 5 minutes softens heavy callosity to ease its removal
|Pyrogallol (pyrogallic acid)||A powerful analgesic, non-self-limiting, caustic reducing agent. It may be used in the treatment of recalcitrant verrucae or neurovascular corns in areas of skin overlying a healthy layer of fibrofatty padding. It should only be used with great caution as its action continues after application has ceased and can lead to severe tissue breakdown that is slow to heal. It is incompatible with alkalis, iron salts, oxidizing agents and ammonium salts|
1. 20% pyrogallol ointment for the treatment of neurovascular corns
2. 40% pyrogallol ointment for the treatment of VP
3. WP ointment (20% pyrogallol, 20% wheat germ oil) for the treatment of tough, fibrous, hyperkeratotic plantar lesions
|Phenol||An analgesic, corrosive caustic. It is used as an 80% solution (liquefied phenol) to destroy soft-tissue lesions such as VP, or nail matrices (three applications, each of 1 minute duration). Its action is quenched by dilution with IMS or isopropyl alcohol. Healing is delayed for several weeks after its application|
|Glacial acetic acid||A weakly acidic mild caustic that is crystalline at 14°C|
1. As a paint to hard or vascular corns, or VP (return period 14-21 days)
2. As a paint to VP, alternating with silver nitrate 75% (in a similar manner to trichloroacetic acid)
3. To neutralize KOH (see above: KOH, point 1)
|Nitric acid||A powerful analgesic oxidizing caustic agent with a superficial action that offers a 'one-off' VP treatment|
1. Applied to VP with a glass rod and left in situ for 5 minutes, followed by phenol solution 10%; the skin stains bright yellow
2. The lesion is saturated with phenol solution 5% for 5 minutes, then with nitric acid for 20-30 seconds, then once again with phenol solution 5%
|Strong iodine solution (iodine solution 10%; iodine fortis)||A strong astringent and vesicant agent. It is incompatible with many topical medicaments, and can cause sensitivity reactions in some patients|
1. to shrink nail tufts
2. to shrink hypergranulation tissue
|Formaldehyde||A strongly astringent and antiseptic agent used in the treatment of VPs (the skin surrounding the lesion should be protected with petroleum jelly; sensitivity is likely)|
1. 10% formaldehyde in collodion, painted on daily
2. 36% formaldehyde solution, painted on daily
|Cryosurgery||The topical application of liquid nitrogen (at -196°C) or nitrous oxide (at -88.5°C) to destroy small soft-tissue lesions; the cell cytoplasm must be reduced to and maintained at -24°C or lower for at least 1 minute, and repeated for two further freezing episodes between which the area has been allowed to thaw. Cryosurgery is more effective when any overlying hyperkeratosis is removed before freezing|
|Hyfrecation||Tissue destruction by initial fulguration (outlining and superficial charring) of the lesion by the application of high-frequency electrical energy), then electrodesiccation (electrocautery) of the lesion by the release of electrical energy whilst the probe is inserted into the lesion|
|Electrosurgery||Tissue removal using high-frequency energy waves to incise through tissue|
Note: Please also refer to the text entries for each listed agent.
IMS, industrial methylated spirit; VP, verrucae pedis.
n a colorless, highly corrosive liquid that may give off suffocating brown fumes of nitrogen dioxide on exposure to air. Commercially prepared nitric acid is a powerful oxidizing agent used in photoengraving and metallurgy.
pertaining to or containing nitrogen in one of its higher valences.
a highly caustic, fuming acid that has a characteristic choking odor. It was used at one time in the immediate treatment of rabid animal bites to prevent rabies becoming established, and as a cauterizing agent in the eradication of various kinds of warts. It is also used in the form of its potassium and sodium salts. It can be fatal if swallowed, and large amounts of nitric acid applied to the skin can cause necrosis. The antidote for nitric acid poisoning is an alkali or sodium bicarbonate applied liberally.
is produced during the ensiling process and animals in confined spaces and exposed to silo gas may develop severe respiratory disease due to irritation of the alveolar epithelium. Called also silo-filler's disease. See also atypical interstitial pneumonia.