Ammonia Toxicity Medication

Management of toxic exposure to ammonia is largely supportive, and medical therapy is directed at hypoxia, bronchospasm, acute lung injury (ALI), hypovolemia, and burns of the skin and eyes.

Antibiotics and corticosteroids are controversial therapies following ammonia inhalation and ingestion exposures.

Although antibiotics and corticosteroids are often used in the acute treatment of patients with inhalation injury, neither has been shown to improve outcome and many believe that corticosteroids may actually increase morbidity. Corticosteroids are recommended to treat bronchospasm in patients with underlying reactive airways disease and acute inhalation injury or for chronic respiratory complications that follow an acute inhalation injury. Patients experiencing signs of airway edema after caustic exposure may benefit from IV administration of dexamethasone (adults: 10 mg; children: 0.6 mg/kg up to 10 mg max).

Use of steroids for the treatment of caustic injuries after caustic ingestion is still very controversial. Intravenous corticosteroids and antibiotics administration can be considered in symptomatic patients following ammonia ingestion with grade IIb (near-circumferential) caustic injuries. Presumably, corticosteroids are administered in order to decrease the incidence and severity of esophageal strictures that occur during healing from significant alkaline injuries. Antibiotics are given because of increased risk of mediastinitis associated with full-thickness esophageal alkaline corrosive burns and steroid use. Although controlled animal studies do support the use of these therapies, no well-controlled human trials have been performed; thus, corticosteroids and antibiotics should be administered in consultation with a GI specialist and surgeon.

If steroids are administered, the recommended dose is 1-2 mg/kg/d of methylprednisolone for 3 weeks followed by gradual tapering. If antibiotics are administered, a broad-spectrum antibiotic (eg, second-generation cephalosporins) is appropriate.

The decision to continue or stop corticosteroid and antibiotic therapy is based on endoscopic findings. Discontinue steroid and antibiotic therapies for patients with no injury or mild mucosal inflammation or ulceration, as they are not at risk for stricture formation. Furthermore, patients with severe transmural burns are at risk for stricture formation, but steroid therapy will not alter their risk. Thus, antibiotic therapy alone is recommended for this group to diminish their risk of mediastinitis. Patients with extensive superficial ulceration or deep discrete or circumferential ulcerations are at risk for stricture formation and may benefit from steroid administration. Consider administering corticosteroids and antibiotics to this group of patients.

Class Summary

Bronchodilators selectively stimulate beta 2-adrenergic receptors of the bronchial tree and lungs. Bronchodilation results from relaxation of bronchial smooth muscle, which relieves bronchospasm and reduces airway resistance.

Albuterol, salbutamol (Proventil, Ventolin)

Beta 2-agonist is used for the treatment of bronchospasm. Relaxes bronchial smooth muscle by action on beta 2-receptors with little effect on cardiac muscle contractility.

Class Summary

Are sometimes considered for the treatment of acute lung injury (ALI). However, positive end-expiratory pressure (PEEP) may be much more useful than diuretics for optimizing oxygenation because ALI is secondary to alveolar capillary injury, not excess fluid. Nonetheless, a trial of diuretics can be considered in patients with evidence of concomitant fluid overload.

Furosemide (Lasix)

Loop diuretic; inhibits sodium chloride reabsorption in the ascending loop of Henle. Administer IV because this allows for superior potency and a higher peak concentration, despite an increased incidence of adverse effects, particularly ototoxicity (rare).

Class Summary

Although expensive, topical Silvadene has antipseudomonal properties in addition to coverage for most gram-positive organisms.

For eye exposures, antibiotic eye preparations will reduce risk of infection secondary to tissue injury.

Silver sulfadiazine 1% (Silvadene)

Useful in prevention of infections from second- or third-degree burns. Has bactericidal activity against many gram-positive and gram-negative bacteria including yeast.

Wash burn before application to remove previously applied agent.

Not for ophthalmic and facial use.

Other products may be used instead of silver sulfadiazine for partial thickness burns; these include TransCyte, Acticoat, or Biobrane.

Ciprofloxacin ophthalmic (Ciloxan)

Fluoroquinolone with activity against pseudomonads, streptococci, MRSA, S epidermidis, and most gram-negative organisms, but no activity against anaerobes. Inhibits bacterial DNA synthesis and growth.

Neomycin 5% is described in much of the literature on ammonia-related eye injury; however, newer broad-spectrum antibiotics have fewer adverse effects

Erythromycin ophthalmic (E-Mycin)

Indicated for infections caused by susceptible strains of microorganisms and for prevention of corneal and conjunctival infections

Class Summary

Induces cycloplegia by blocking the body's parasympathetic (cholinergic) effects in the eye. This is beneficial to prevent ciliary spasm. Should be used in consultation with the ophthalmology service.

Cyclopentolate (AK-Pentolate)

Blocks muscle of ciliary body and sphincter muscle of iris from responding to cholinergic stimulation, thus causing mydriasis and cycloplegia.

Induces mydriasis in 30-60 min and cycloplegia in 25-75 min; these effects last up to 24 hours

Homatropine (Isopto Homatropine)

Blocks responses of sphincter muscle of iris and muscle of ciliary body to cholinergic stimulation, producing pupillary dilation (mydriasis) and paralysis of accommodation (cycloplegia).

Induces mydriasis in 10-30 min and cycloplegia in 30-90 min; these effects last up to 48 h.

Tropicamide (Mydriacyl)

Blocks sphincter muscle of iris and muscle of ciliary body from responding to cholinergic stimulation

Class Summary

Decrease the formation of fibroblasts on the cornea and may limit intraocular inflammation. However, may potentiate infection. Should be administered only in consultation with the ophthalmology service.

Prednisolone ophthalmic (Pred Forte)

Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.

Note that ophthalmologic steroids are controversial; discuss their use with ophthalmology. Also, steroid-antibiotic combination may be useful.

Fluorometholone (FML)

Suppresses migration of polymorphonuclear leukocytes and reverses capillary permeability

Rimexolone (Vexol)

Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.

Class Summary

Used primarily for pain relief. Duration of action is relatively short-lived, limiting usefulness of local anesthetics outside of the hospital or clinic setting.

Proparacaine 0.5% (Alcaine)

Has rapid onset of anesthesia that begins within 13-30 sec after instillation. However, has short duration of action of about 15-20 min.

Least irritating of all topical anesthetics. Prevents initiation and transmission of impulse at nerve cell membrane by stabilizing and decreasing ion permeability.

Onset of action occurs within 20 s of application.

Anesthetic effect may last up to 10-15 min