- Molecular NameFamotidine
- SynonymFamotidina [Spanish]; Famotidinum [Latin]
- Weight337.453
- Drugbank_IDDB00927
- ACS_NO76824-35-6
- Show 3D model
- LogP (experiment)-0.726
- LogP (predicted, AB/LogP v2.0)-0.29
- pka6.88
- LogD (pH=7, predicted)-0.47
- Solubility (experiment)1.1 mg/ml
- LogS (predicted, ACD/Labs)(ph=7)-2.35
- LogSw (predicted, AB/LogsW2.0)1.74
- Sw (mg/ml) (predicted, ACD/Labs)0.2
- No.of HBond Donors8
- No.of HBond Acceptors9
- No.of Rotatable Bonds7
- TPSA237.75
- StatusFDA approved
- AdministrationN/A
- PharmacologyA histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD).
- Absorption_value45.0
- Absorption (description)After intravenous administration, the plasma famotidine concentration–time profile exhibits a biexponential decay. Famotidine is readily but incompletely absorbed after oral administration. There are three formulations available (tablet, capsule and suspension), which appear to be bioequivalent.
- Caco_2N/A
- Bioavailability42.0
- Protein binding17.5
- Volume of distribution (VD)In adults: 0.94 to 1.33 L/kg; in infants: 0.82 L/kg. In paediatric patients (aged between 2 and 7 years): 1.4 L/kg.
- Blood/Plasma Partitioning ratio (D_blood)N/A
- MetabollsmOnly a small amount of the drug is metabolised in the liver to famotidine S-oxide and the remainder is excreted unchanged in urine (approx. 67%).
- Half lifeDistribution half-life is approx. 0.18~0.5 h in adults. Elimination half-life is approx. 3 h in adults, which can increase to 24 h in patients with suppressed urine excretion. The elimination half-life for infants is approx. 10 h. Elimination half-life is 3.3 h in paediatric patients with normal kidney function, aged between 2 and 7 years.
- ExcretionA prolongation of elimination half-life and a decrease in total body clearance and renal clearance are observed in patients with renal failure indicating that dosage adjustment may be necessary in patients who have renal insufficiency. No significant changes occur in famotidine disposition in patients with cirrhosis indicating that no reduction in drug dosage should be necessary in these patients. The pharmacokinetics and pharmacodynamics of intravenous famotidine appear to be similar in both children over the age of 1 year and adults.
- Urinary ExcretionN/A
- Clerance0.19 to 0.43 L/min. In patients with end-stage renal failure: 0.034 L/min. In paediatric patients with normal kidney function: 0.3 L/h/kg.
- ToxicityConvulsions and mental deterioration have been reported in the elderly with renal failure owing to grossly elevated plasma and cerebrospinal fluid concentrations of the drug. Toxic epidermal necrolysis can also occur. Since 1992, there have been 60 reports of serious blood dyscrasias.
- LD50 (rat)N/A
- LD50 (mouse)LD50 = 4686 mg/kg