Usage
- Phenolphthalein is primarily prescribed for the short-term symptomatic relief of constipation. It is also used for bowel cleansing before medical procedures such as colonoscopies or surgeries.
- Pharmacological classification: Stimulant laxative.
- Mechanism of action: Phenolphthalein stimulates intestinal motility by irritating the smooth muscle of the intestinal wall and increasing water and electrolyte secretion into the intestinal lumen. This leads to increased peristalsis and bowel evacuation.
Alternate Names
- No officially recognized alternate names.
- Brand names: Many brand names previously contained phenolphthalein but it has been withdrawn from the U.S. market. Some previous brand names included Correctol and Ex-Lax (now formulated with different active ingredients). Some brands containing phenolphthalein may still be available in other countries.
How It Works
- Pharmacodynamics: Phenolphthalein increases intestinal motility and fluid accumulation in the colon, leading to bowel evacuation. It acts primarily on the large intestine (colon).
- Pharmacokinetics:
- Absorption: Up to 15% of an oral dose is absorbed from the gastrointestinal tract.
- Metabolism: Absorbed phenolphthalein is conjugated in the liver (primarily glucuronidation).
- Elimination: Excreted primarily in the feces as both free and conjugated forms. A small amount is excreted in the urine, particularly after larger doses. The enterohepatic circulation may prolong the drug’s effect. Urine may turn pink or red in alkaline conditions due to the presence of phenolphthalein.
Dosage
Phenolphthalein is no longer available in many countries, including the US, due to safety concerns. The following information is provided for historical reference only and should not be interpreted as current recommendations for clinical practice.
Standard Dosage (Historical)
Adults:
- 30–200 mg daily, taken at bedtime. The maximum daily dose should not exceed 270 mg.
Children:
- 2-5 years: 15–30 mg daily.
- 6-11 years: 30–60 mg daily.
- 12 years and older: Follow adult dosing.
Special Cases:
Due to the potential risks, phenolphthalein is generally not recommended for use in the elderly, patients with renal or hepatic impairment, or those with comorbid conditions. Safer alternatives should be considered.
Clinical Use Cases (Not applicable anymore due to safety concerns)
Phenolphthalein is no longer recommended for clinical use, particularly in intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations.
Side Effects
Common Side Effects
- Abdominal cramps
- Diarrhea
- Skin rash
- Discoloration of urine (pink or red in alkaline conditions)
Rare but Serious Side Effects
- Allergic reactions
- Stevens-Johnson syndrome
- Electrolyte imbalances (with prolonged use)
- Cathartic colon (with chronic use)
Contraindications
- Hypersensitivity to phenolphthalein
- Intestinal obstruction
- Inflammatory bowel disease
- Undiagnosed abdominal pain
- Acute surgical abdomen
Drug Interactions
- Antacids: May reduce the effectiveness of phenolphthalein.
- Diuretics and corticosteroids: May increase the risk of dehydration and electrolyte imbalances.
- Other medications: May interfere with the absorption of other orally administered drugs due to increased gastrointestinal transit.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Not established. Due to potential risks, phenolphthalein is generally avoided during pregnancy.
- Breastfeeding: Phenolphthalein may be excreted in breast milk and could cause diarrhea in infants. It is generally avoided during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Stimulant laxative that irritates the intestinal wall and increases fluid secretion.
- Side Effects: Abdominal cramps, diarrhea, skin rash, urine discoloration. More serious but rarer effects include allergic reactions, Stevens-Johnson Syndrome, electrolyte imbalances, and cathartic colon (with prolonged use).
- Contraindications: Hypersensitivity, intestinal obstruction, inflammatory bowel disease, undiagnosed abdominal pain, acute surgical abdomen.
- Drug Interactions: Antacids, diuretics, corticosteroids, other orally administered medications.
- Pregnancy & Breastfeeding: Generally avoided due to potential risks.
- Dosage: No longer recommended for use. Historical dosages are mentioned above for informational purposes only.
Popular Combinations (No longer relevant)
There are no longer any commonly used drug combinations involving phenolphthalein.
Precautions
- Avoid long-term use due to the risk of dependence, cathartic colon, and electrolyte imbalances.
- Not suitable for use in pregnancy and breastfeeding.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Phenolphthalein?
A: Phenolphthalein is no longer recommended for use due to safety concerns. Historical dosages are mentioned above for informational purposes only.
Q2: What are the potential side effects of Phenolphthalein?
A: Common side effects include abdominal cramps, diarrhea, and skin rash. Rare but serious side effects include allergic reactions and Stevens-Johnson Syndrome.
Q3: Is Phenolphthalein safe to use during pregnancy?
A: No, phenolphthalein is generally avoided during pregnancy due to potential risks to the fetus.
Q4: Can Phenolphthalein be used while breastfeeding?
A: No, Phenolphthalein may be excreted in breast milk and could cause diarrhea in infants.
Q5: What conditions does phenolphthalein treat?
A: Historically, phenolphthalein was used to treat constipation and for bowel cleansing before medical procedures. However, it is no longer recommended for these purposes.
Q6: How does phenolphthalein work?
A: Phenolphthalein acts as a stimulant laxative, irritating the intestinal wall and increasing fluid secretion, leading to bowel movements.
Q7: What are the contraindications for using phenolphthalein?
A: Contraindications include hypersensitivity to phenolphthalein, intestinal obstruction, inflammatory bowel disease, and undiagnosed abdominal pain.
Q8: Are there any drug interactions with phenolphthalein?
A: Yes, phenolphthalein can interact with antacids, diuretics, corticosteroids, and other orally administered medications.
Q9: What is cathartic colon?
A: Cathartic colon is a condition characterized by colonic denervation and atony, resulting in decreased motility and potentially leading to chronic constipation. It can be caused by the long-term misuse of stimulant laxatives like phenolphthalein.
Q10: Why is phenolphthalein no longer recommended?
A: Phenolphthalein has been withdrawn from the market in many countries due to concerns about its potential carcinogenicity and other safety risks.
