Pill Identification: L194
The round white pill imprinted with "L194" is famotidine 20 mg, an H2-receptor antagonist used to treat acid-related gastrointestinal disorders.
Medication Overview
- Famotidine is a highly selective histamine H2-receptor antagonist that is approximately 20-50 times more potent than cimetidine and 8 times more potent than ranitidine on a weight basis 1
- The 20 mg dose is FDA-approved and commonly prescribed for treatment of duodenal ulcer, gastric ulcer, gastroesophageal reflux disease, and Zollinger-Ellison syndrome 2
Standard Dosing Regimens
- For active ulcer treatment: Famotidine 20 mg twice daily or 40 mg at bedtime achieves healing rates similar or superior to cimetidine 800 mg daily or ranitidine 300 mg daily 1
- For ulcer prevention: A single 20 mg dose at bedtime is effective in preventing duodenal ulcer relapse 3
- Dose equivalency reference: Famotidine 20 mg twice daily is equivalent to omeprazole 20 mg once daily, lansoprazole 30 mg once daily, or ranitidine 150 mg twice daily 4
Pharmacokinetics
- After oral administration, antisecretory activity begins within 1 hour, reaches maximum effect in 1-3 hours, and lasts 10-12 hours 5
- Peak plasma concentrations are attained within 2-4 hours with oral bioavailability of 40-50% 6
- The elimination half-life is approximately 2.8 hours in healthy subjects, with 70% eliminated unchanged in urine 5, 6
Safety Profile
- Famotidine has an excellent tolerability profile with an estimated 18.8 million patients treated worldwide since 1985 2
- Unlike cimetidine, famotidine does not have antiandrogenic effects and does not notably bind to cytochrome P-450, resulting in minimal clinically significant drug interactions 2, 3
- The drug is generally well tolerated in patients with cardiovascular, renal, or hepatic dysfunction, with doses up to 800 mg daily tolerated in Zollinger-Ellison syndrome 2
Dosing Adjustments
- Renal insufficiency: Dosage reduction is required as total body and renal clearances correlate significantly with creatinine clearance 6
- Elderly patients: Maintenance dosage should be reduced due to decreased clearance 6
- Antacid coadministration: Potent antacids reduce oral absorption by 20-30%; separate administration timing is advisable 6