Usage
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Alum, in medical contexts, primarily refers to aluminum salts like aluminum sulfate, aluminum hydroxide, or potassium alum. These salts are used to treat various conditions, including:
- Hyperhidrosis: Aluminum chloride is a primary active ingredient in many antiperspirants, reducing excessive sweating by blocking sweat ducts.
- Water purification: Aluminum sulfate is used as a coagulant in water treatment to remove impurities.
- Minor bleeding control: Alum can be applied topically to stop minor cuts from bleeding due to its astringent properties.
- Vaccine adjuvant: Aluminum salts enhance the immune response to vaccines.
- Antacid (aluminum hydroxide): Neutralizes stomach acid to relieve heartburn, acid indigestion, and upset stomach.
- Treatment of bladder cancer: Alum irrigation can be used to control hematuria (blood in the urine) in cases of inoperable bladder cancer, especially in patients with renal impairment where silver nitrate cannot be used.
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Pharmacological Classification:
- Astringent
- Antiperspirant
- Coagulant
- Antacid (aluminum hydroxide)
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Mechanism of Action: The mechanism of action varies depending on the specific alum salt and its application. Generally, alum acts through:
- Astringent action: Causes contraction of tissues, constricting blood vessels and reducing bleeding.
- Blocking sweat ducts (aluminum chloride): Forms a plug within the sweat duct, reducing sweat secretion.
- Coagulation (aluminum sulfate): Neutralizes the electrical charge of suspended particles in water, causing them to clump together and settle out.
- Neutralization of gastric acid (aluminum hydroxide): Reacts with hydrochloric acid in the stomach to form aluminum chloride and water, thus raising gastric pH.
Alternate Names
- Aluminum sulfate (alum), potash alum (potassium alum), aluminum hydroxide, aluminum chloride
How It Works
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Pharmacodynamics:
- Aluminum hydroxide (antacid): Neutralizes gastric acid by increasing gastric pH. This can lead to reduced pepsin activity.
- Aluminum chloride (antiperspirant): Precipitates proteins and forms plugs within sweat ducts, inhibiting sweat secretion.
- Aluminum sulfate (coagulant): Causes colloidal particles in water to aggregate and precipitate, aiding clarification.
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Pharmacokinetics:
- Absorption: Oral absorption of aluminum salts is generally poor.
- Metabolism: Minimal metabolism of aluminum salts occurs.
- Elimination: Primarily renal excretion, with some aluminum potentially eliminated in feces.
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Mode of Action: Depends on the specific alum salt and its application (see above).
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Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: Not typically associated with these mechanisms, except for reduced pepsin activity by aluminum hydroxide due to increased gastric pH.
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Elimination Pathways: Primarily renal excretion for most alum salts.
Dosage
Standard Dosage
Adults: Aluminum hydroxide (antacid): 30-50ml every 3-4 hours, or 1 and 3 hours after meals and at bedtime.
Children: Aluminum hydroxide (antacid):
- Children: 5-15ml every 3-6 hours, or 1 and 3 hours after meals and at bedtime.
- Infants: 1-2 ml/kg per dose, given after meals and at bedtime.
Special Cases:
- Elderly Patients, Patients with Renal Impairment, Patients with Hepatic Dysfunction, Patients with Comorbid Conditions: Use aluminum hydroxide with caution in these populations due to the risk of aluminum toxicity and other potential complications.
Clinical Use Cases
Dosage recommendations vary depending on the specific alum salt and application (e.g., water purification, hyperhidrosis treatment). Dosage guidelines for aluminum hydroxide as an antacid are provided above.
Side Effects
Common Side Effects
- Aluminum hydroxide: Constipation, nausea, diarrhea, headache.
- Aluminum chloride: Skin irritation, dryness, itching.
Rare but Serious Side Effects
- Aluminum toxicity (primarily in patients with renal impairment): Encephalopathy, osteomalacia, hypophosphatemia.
Contraindications
- Hypersensitivity to aluminum salts.
- Severe renal impairment (for aluminum-containing products).
- Concomitant use with pazopanib or raltegravir (aluminum hydroxide).
Drug Interactions
Aluminum hydroxide can interact with numerous medications, including:
- Tetracycline antibiotics
- Quinolone antibiotics
- Iron supplements
- Digoxin
- Pazopanib
- Raltegravir
Pregnancy and Breastfeeding
Aluminum hydroxide should be used with caution during pregnancy and breastfeeding, only if clearly needed. Limited data are available regarding transfer to breast milk, but aluminum is present in human milk naturally. Some authorities recommend monitoring breastfed infants for potential side effects.
Drug Profile Summary
- Mechanism of Action: Varies depending on the alum salt (see above).
- Side Effects: See above.
- Contraindications: See above.
- Drug Interactions: See above.
- Pregnancy & Breastfeeding: Use with caution.
- Dosage: Varies depending on the alum salt (see above).
- Monitoring Parameters: Renal function (in patients with pre-existing renal disease).
Precautions
- Pre-existing renal disease
- Dehydration
- Frequent alcohol consumption
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Alum (aluminum hydroxide)?
A: Adults: 30-50ml every 3-4 hours or as directed. Children: Dosage based on age and weight (see above).
Q2: What are the common side effects of alum?
A: Side effects can include constipation, nausea, skin irritation, dryness, and itching depending on the specific alum salt.
Q3: Who should not take alum?
A: Individuals with hypersensitivity to aluminum salts and patients with severe renal impairment should generally avoid aluminum-containing products.
Q4: Can alum be used during pregnancy or breastfeeding?
A: Alum should be used cautiously during pregnancy and breastfeeding, only if clearly needed. Consult a healthcare professional for advice.
Q5: How does aluminum hydroxide work as an antacid?
A: It neutralizes stomach acid by reacting with hydrochloric acid to form aluminum chloride and water.
Q6: What is the role of alum in water purification?
A: Aluminum sulfate acts as a coagulant, causing impurities to clump together and precipitate out of the water.
Q7: How does aluminum chloride work as an antiperspirant?
A: It forms plugs within sweat ducts, reducing sweat secretion.
Q8: Are there any drug interactions with aluminum hydroxide?
A: Yes, it can interact with various medications. See above for a list of examples.
Q9: What are the signs of aluminum toxicity?
A: Signs can include encephalopathy, osteomalacia, and hypophosphatemia, primarily occurring in individuals with impaired renal function.
