What is Phloroglucinol?
Phloroglucinol (also spelled floroglucino in some languages) is a natural phenolic compound (1,3,5-trihydroxybenzene) used primarily as an antispasmodic medication for treating abdominal pain in irritable bowel syndrome and acute renal colic. 1, 2
Chemical Structure and Properties
- Phloroglucinol is a benzene ring with three hydroxyl groups positioned symmetrically at the 1,3, and 5 positions 3
- It exists naturally in plants, algae, and microorganisms, though pharmaceutical preparations are typically synthetic 4, 5
- The compound acts as a peroxidase inhibitor with antioxidant, anti-inflammatory, and spasmolytic properties 3
Primary Clinical Uses
- Irritable bowel syndrome (IBS): Phloroglucinol 50mg three times daily significantly reduces abdominal pain, stool frequency, urgency, mucus passage, incomplete defecation sensation, and bloating 2
- In acute IBS pain exacerbations, the combination of phloroglucinol/trimethylphloroglucinol (62.2mg/80mg) two pills three times daily for 7 days produces a 57.8% reduction in pain intensity versus 46.3% with placebo 1
- Acute renal colic: Used to control spasmodic pain, though specific dosing studies were not provided in the evidence 3
Mechanism of Action
- Phloroglucinol and its methylated derivative (trimethylphloroglucinol) act directly on smooth muscle as antispasmodic agents 1
- The compound does not work through anticholinergic mechanisms, making it distinct from other antispasmodics 1
Additional Biological Activities
- Antimicrobial properties against bacteria, fungi, and viruses have been documented 5
- Anti-diabetic, anti-thrombotic, radio-protective, and anti-cancer activities demonstrated in research settings 3
- Used in pharmaceutical, cosmetic, textile, paint, and dyeing industries 4
Safety Profile
- At therapeutic doses: Well tolerated up to 300 mg/kg body weight in animal studies 3
- At low concentrations (0.2-1 mM or 25.2-126 μg/ml): No cytotoxicity observed in differentiated somatic cells 3
- At high concentrations (≥10 mM): Dose-dependent toxic effects including protein synthesis interruption, cellular machinery disruption, autophagy, and apoptosis 3
- Tumor or immortalized cells appear more susceptible to toxic effects than normal cells 3
Clinical Efficacy Data
- In a 100-patient study, 68% completed treatment with phloroglucinol 50mg three times daily for 2 months, showing statistically significant improvement in most IBS symptoms (p<0.001 for pain, stool frequency, urgency, mucus passage; p=0.001 for incomplete defecation and bloating) 2
- A randomized, double-blind, placebo-controlled trial of 300 IBS patients demonstrated 62% achieved ≥50% pain reduction with phloroglucinol/trimethylphloroglucinol versus 47% with placebo (p=0.0078) 1
Important Clinical Considerations
- No response to straining: Phloroglucinol does not improve straining symptoms in IBS patients (p=0.676) 2
- Gender differences: Females show particularly significant improvement in incomplete defecation sensation (p=0.003) 2
- Dropout rates: Approximately 28-32% of patients discontinue treatment in clinical trials, though specific adverse events were not detailed 2