Oxethazaine – Aluminum Hydroxide – Magnesium Hydroxide
Antacid – Mucosal Anesthetic
Action And Clinical Pharmacology: Alumina gel and magnesium hydroxide react chemically to neutralize or buffer existing quantities of stomach acid but have no direct effect on its production. This action increases gastric pH, providing symptomatic relief of hyperacidity.
Gastroscopic observations reveal that alumina gel, especially when swallowed undiluted, forms a diffuse coating over the inflamed gastric mucosa for a variable period of time. Because of this adherent vehicle, oxethazaine exerts a prolonged topical anesthetic action.
Oxethazaine is a topical anesthetic which when applied to the mucous membranes produces a more potent anesthesia of longer duration than either cocaine or lidocaine. An ultra-dilute solution of 0.0005% oxethazaine induces the same duration of anesthesia of rabbit cornea as does the more concentrated 0.25% solution of cocaine; as a 1% solution of lidocaine; or as a 2% solution of procaine.
The higher order of potency of oxethazaine permits clinical use of dilute solutions; a 0.2% concentration of oxethazaine in alumina gel is therapeutically effective. In vitro, oxethazaine produces antispasmodic action on smooth muscle. It antagonizes the action of serotonin on smooth muscle as demonstrated on isolated rabbit jejunum strips.
A wide margin of safety exists between the effective dose of oxethazaine in alumina gel and the oral toxic dose of the compound. In mice, the oral LD50 of oxethazaine is approximately 400 mg of base/kg; when suspended in alumina gel as a vehicle the oral LD50 in mice is 1 012 mg of base/kg. The effective dose, 5 to 10 mL, contains 10 or 20 mg of oxethazaine respectively; this is only 0.2 or 0.4 mg/kg of body weight for a human weighing 50 kg. In humans, toxic effects have not been observed on continued ingestion of recommended therapeutic doses.
Pharmacokinetics: Studies have shown that a small amount of aluminum from aluminum hydroxide is absorbed from the intestine. Approximately 10% of the magnesium in magnesium hydroxide is absorbed from the intestine.
After oral administration of 20 mg oxethazaine contained in 10 mL of alumina gel with magnesium hydroxide, the peak oxethazaine plasma level was approximately 20 ng/mL and occurred about 1 hour after dosing.
Oxethazaine undergoes rapid and extensive biotransformation resulting in a short plasma half-life of approximately one hour. Less than 0.1% unchanged oxethazaine was recovered in the urine within 24 hours. Major metabolites were B-hydroxy-mephentermine and B-hydroxy-phentermine. Mephentermine and phentermine appeared in the plasma in pharmacologically insignificant amounts and their cumulative 24-hour urinary excretion was less than 0.1% of the dose administered.
Indications And Clinical Uses: For the symptomatic relief of peptic ulcer, gastritis, and esophagitis. Symptoms of esophageal irritation are usually relieved in patients who do not respond to antacid therapy alone.
Contra-Indications: This product should not be given to any patient who has demonstrated a sensitivity to it.
The use of aluminum- or magnesium-containing antacids is contraindicated in patients with symptoms of appendicitis since these products may increase the danger of perforation or rupture due to their constipating or laxative effects.
The use of aluminum-containing antacids (except those containing aluminum phosphate) is contraindicated in patients with hypophosphatemia due to the phosphate binding properties of aluminum salts.
The use of magnesium-containing antacids is contraindicated in patients with severe renal function impairment due to increased danger of occurrence of hypermagnesemia.
Manufacturers’ Warnings In Clinical States: Adequate diagnostic studies are recommended. The possibility of gastrointestinal carcinoma should be considered in patients with protracted or recurrent indigestion.
Precautions: The use of magnesium-containing antacids in patients with mild to moderate renal impairment should be carefully monitored due to a possible increased danger of hypermagnesemia.
In patients with chronic renal failure, hyperaluminemia may occur.
Hypophosphatemia may occur with prolonged administration or large doses of aluminum-containing antacids (except aluminum phosphate) especially in patients with an inadequate dietary intake of phosphorus.
Laboratory Tests: Serum phosphate levels should be monitored at monthly or bi-monthly intervals in patients on maintenance hemodialysis who are receiving chronic antacid therapy.
Carcinogenesis, Mutagenesis, and Impairment of Fertility: Long-term animal studies have not been performed to evaluate the carcinogenic or mutagenic potential of Mucaine. No evidence of impaired fertility was revealed during a breeding experiment with male and female rats fed Mucaine orally throughout the experiment. The effect on human fertility is not known.
Pregnancy: A reproduction study performed in rabbits revealed no evidence of harm to the fetus. There are, however, no adequate or well-controlled studies in pregnant women. Use during pregnancy if the benefits outweigh the potential risks.
Lactation: It is not known if Mucaine is excreted in breast milk. Because many drugs are excreted in breast milk, a decision should be made whether to discontinue nursing or to discontinue Mucaine, taking into account the importance of the drug to the mother and the potential risk to the infant.
Children: The safety and effectiveness of Mucaine in children have not been established. Therefore this product is recommended for adult use only.
Adverse Reactions: Hypersensitivity reactions including skin eruptions (dermatitis, urticaria), pruritus, glossitis, angioedema, and collapse have been reported in occasional cases.
If the dose of this product exceeds 60 mL/day, some patients may experience dizziness, faintness, or drowsiness.
Magnesium-containing antacids may cause diarrhea. Aluminum-containing antacids may cause constipation.
Drug Interactions: The rate and/or extent of absorption of many drugs may be increased or decreased when they are used concurrently with aluminum-magnesium hydroxide- containing antacids. Therefore, as a general rule, medication should not be taken within 1 to 2 hours of an antacid, if possible.
An incomplete list of substances for which the above statement has been shown to apply includes; tetracycline, iron salts, chlorpromazine, levodopa, isoniazid, digoxin, H2-antagonists, indomethacin, nitrofurantoin, and dicumarol.
An increase in the plasma level of quinidine and possible toxicity may result if alkalization of the urine occurs during antacid therapy.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: Patients should be observed with symptomatic therapy instituted as indicated by the clinical situation.
Dosage And Administration: The recommended dose is 5 to 10 mL taken 4 times daily, 15 minutes before meals and at bedtime. Do not exceed recommended dosage.
The maximum dose recommended may be decreased following adequate control of the symptoms. The suspension should preferably be taken undiluted; however, if desired, it may be followed by a sip of water.
Availability And Storage: Each 5 mL of oral suspension contains: oxethazaine 10 mg, aluminum hydroxide 300 mg and magnesium hydroxide 100 mg. Nonmedicinal ingredients: artificial flavor, glycerin, methocel, methylparaben, peppermint oil, propylparaben, sodium benzoate, sodium cyclamate and sorbitol solution. Energy: 10 kJ (2.4 kcal). Tartrazine-free. Bottles of 350 and 500 mL. Shake well before use. Keep tightly closed. Store in a cool area. Protect from freezing.
MUCAINE® Axcan Pharma Oxethazaine – Aluminum Hydroxide – Magnesium Hydroxide Antacid – Mucosal Anesthetic