What Is Famotidine?

The main dosage forms of famotidine are tablets, capsules and injections. Histamine H2 receptor antagonist, can inhibit gastric acid secretion. Applicable to gastric and duodenal ulcers, reflux esophagitis, upper gastrointestinal bleeding, Zhuo-Ai syndrome and other symptoms.

The main dosage forms of famotidine are tablets, capsules and injections. Histamine H2 receptor antagonist, can inhibit gastric acid secretion. Applicable to gastric and duodenal ulcers, reflux esophagitis, upper gastrointestinal bleeding, Zhuo-Ai syndrome and other symptoms.

Chinese name

Famotidine

Foreign name

Famotidine

Alias

Gao Shuda, Bao Weijian; Baoweijian; Thiazolamide

Molecular formula

C8H15N7O2S3

Molecular weight

337.45

Storage method

15-25 ° C, protected from light

Introduction to famotidine compounds

Famotidine

Chinese name: famotidine

Chinese alias: 3-[[[2-[(Diaminomethylene) amino] -4-thiazolyl] methyl] thio] -N-sulfamoylpropionate; Baoweijian; Baoweijian; Method Modin; Gosuda; Sulfadine; Methiothiazide; Carmat; Gastroda; Befadine; Yuyangning; Non-destructive; Thiazolamide;

English name: famotidine

English alias: Famotidine; pepcid; pepdul; fibonel; peptan; Famotidine (Patented-No Supply); 3-[[[[2-[(Aminoiminomethyl) amino] -4-thiazolyl] methyl] thio] -N- (aminosulfonyl) propanimidamide Famotidinum; Gaster; Gastropen; MK-208; Pepcidine; Pepdine

CAS number: 76824-35-6

Molecular formula: C ₈ H ₁₅ N ₇ O ₂ S ₃

Structural formula:

Molecular weight: 337.44500

Exact mass: 337.004500

PSA: 235.25000

LogP: 3.11400

Famotidine physical and chemical properties

Appearance and properties: This product is white or slightly yellow-white crystal, odorless and slightly bitter. Soluble in dimethylformamide or glacial acetic acid, difficult to dissolve in methanol, extremely difficult to dissolve in water, acetonitrile, absolute ethanol or acetone, almost insoluble in chloroform or ether

Density: 1.83 g / cm ³

Melting point: 163-164 ° C

Flash point: 354.4ºC

Water solubility: 1.1 mg / mL

Storage conditions: Store in a cool, dry and dark sealed container. Protect containers / cylinders from physical damage.

Famotidine Safety Information

Customs Code: 29350009090

WGK Germany: 2

Danger category code: R20 / 21/22

Safety instructions: S22-S24 / 25

RTECS number: UA2300000

Dangerous goods mark: T ^[1]

Famotidine production method

Prepared from fluorenylthiourea. Amidinothiourea and 1,3-dichloroacetone are cyclized to form 2-guanidino-4-chloromethylthiazole, which is then reacted with thiourea and then reacted with chloropropionitrile to form 2-guanidino-4- [ (Cyanoethylthio) methyl] thiazole is subjected to alcoholysis with methanol, and is amidated to obtain famotidine ^[1] .

Famotidine uses

This product is a histamine H2 receptor antagonist. It has a significant inhibitory effect on gastric acid secretion, and its intensity is more than 30 times stronger than cimetidine and 6-10 times stronger than ranitidine. It is clinically used for gastric and duodenal ulcers, stress ulcers, acute Gastric mucosal bleeding, gastrinoma, and reflux esophagitis.

Famotidine Pharmacopoeia Standard

Famotidine source (name), content (potency)

This product is [1-amino-3-[[[2-[(diaminomethylene) amino] -4-thiazolyl] -methyl] thio] propylene] sulfonamide. Calculated on dry basis, containing C ₈ H ₁₅ N ₇ O ₂ S ₃ shall not be less than 98.0%.

Famotidine traits

This product is a white or off-white crystalline powder; it has a slightly bitter taste; it becomes darker when exposed to light.

This product is slightly soluble in methanol, very slightly soluble in acetone, almost insoluble in water or chloroform; easily soluble in glacial acetic acid.

Melting point

The melting point of this product (Appendix VIC of Part Two of the 2010 Pharmacopoeia) is 160-165 ° C, and it will decompose at the same time when melting.

Famotidine identification

(1) Take this product and add pH 4.5 potassium dihydrogen phosphate buffer solution (take 13.6 g of potassium dihydrogen phosphate, dissolve and dilute to 1000 ml with water, adjust the pH to 4.5), make a solution containing 15 g per 1 ml, according to Ultraviolet-visible spectrophotometry (Appendix IVA of Pharmacopoeia Part II of the 2010 edition) determined that it had the maximum absorption at a wavelength of 266 nm and the absorbance was 0.45 to 0.48.

(2) The infrared light absorption spectrum of this product should be the same as that of the control ("Infrared Spectra of Drugs" 781).

Famotidine check

Clarity and color of acid solutions

Take 0.5g of this product, add 10ml of hydrochloric acid solution (4.5 100) to dissolve, the solution should be clear and colorless; if color is developed, compare with the yellow colorimetric standard colorimetric solution (Appendix A of the second edition of the Pharmacopoeia of 2010 edition, method A) Must not be deeper.

relative substance

Take an appropriate amount of this product, add an appropriate amount of methanol to dissolve, and use phosphate buffer solution (take 13.6 g of sodium dihydrogen phosphate, put in 900 ml of water, adjust the pH value to 7.0 soil 0.1 with 1 mol / L sodium hydroxide solution, add water to 1000 ml, mix Mix evenly, take 930ml and 70ml of acetonitrile, and then dilute to make a solution containing 0.5mg of famotidine per 1ml as the test solution; precisely measure the appropriate amount of the test solution and quantitatively dilute it with the above phosphate buffer solution. A solution containing 5 ug per 1 ml was prepared as a control solution. Measured by high performance liquid chromatography (Appendix VD of Part Two of the Pharmacopoeia 2010), using octadecylsilane bonded silica as a filler (recommended column: Kromasil Cl8, 250mm × 4.6mm, 5um or equivalent column) ); Acetate buffer solution (take 13.6g of sodium acetate, put in 900ml of water, adjust the pH to 6.0 ± 1.0 with glacial acetic acid, add water to 1000ml)-acetonitrile (93: 7) as the mobile phase A, and acetonitrile as the mobile phase Phase B, detection wavelength is 270nm, flow rate is 1.5ml per minute; column temperature is 35 ° C. Gradient elution was performed according to the following table. Take about 25mg of famotidine, add 2ml of acetonitrile and 2ml of the above phosphate buffer to dissolve, add 3ml of 0.5mol / L hydrochloric acid solution, heat in a water bath at 40 ° C for 5 minutes, add 3ml of 0.5mol / L sodium hydroxide solution, and then add 1mol 5ml / L sodium hydroxide solution, heated in a 60 ° C water bath for 5 minutes, added 1mol / L hydrochloric acid solution 5ml, and diluted with the above-mentioned phosphate buffer solution to make a solution containing about 0.5mg per 1ml as a system suitability solution. Take 20u1 of this solution and inject it into the liquid chromatograph, record the chromatogram and adjust the flow ratio. The retention time of the famotidine peak is about 10 minutes, and the retention time of the impurity I and impurity II peaks relative to the famotidine peak. About 0.7 and 1.2. The theoretical plate number is calculated to be not less than 5000 according to the famotidine peak, and the resolution of the famotidine peak and the adjacent impurity peaks should meet the requirements. 20ul of the control solution was accurately measured and injected into the liquid chromatograph, and the detection sensitivity was adjusted so that the height of the main component chromatographic peak was about 10% of the full scale. Then accurately measure 20ul each of the control solution and the test solution, inject them into the liquid chromatograph, and record the chromatogram. If there are impurity peaks in the chromatogram of the test solution, the area of a single impurity peak must not be greater than 0.3 times (0.3%) the area of the main peak of the control solution, and the sum of the area of each impurity peak must not be greater than the main peak surface of the control solution (1.0%).

Time (minutes)	Mobile phase A (%)	Mobile phase B (%)
0	100	0
15	100	0
42	52	48
43	100	0
48	100	0

(According to the "Pharmacopoeia of the People's Republic of China" (the first supplement of the 2010 edition) delete the original [check] residual solvent items).

Loss on drying

Take this product and dry it at 105 to constant weight, and the weight loss shall not exceed 0.5% (Appendix L of Part Two of the Pharmacopoeia of 2010 Edition).

Residue on ignition

Take this product 1.0g. In accordance with the law (Appendix N of Part Two of the Pharmacopoeia 2010), the residual residue shall not exceed 0.1%.

Heavy metal

Take the residue left under the burning residue and inspect it according to law (Appendix H of the 2010 edition of the Pharmacopoeia, the second method). The heavy metal must not exceed 10 parts per million.

Determination of famotidine

Take about 0.12g of this product, accurately weigh, add 20ml of glacial acetic acid and 5ml of acetic anhydride, add 1 drop of crystal violet indicator solution, titrate with perchloric acid titration solution (0.1mol / L) until the solution becomes green, and The results of the titrations are corrected with a blank test. Each 1ml of perchloric acid titration solution (0.1mol / L) is equivalent to 16.87mg of C ₈ H ₁₅ N ₇ O ₂ S ₃ .

Famotidine Categories

H2 receptor blockers.

Famotidine storage

Shaded and sealed.

Famotidine

(1) famotidine tablets (2) famotidine injection (3) famotidine capsules (4) famotidine particles

Famotidine version

The 2010 Edition of the Pharmacopoeia of the People's Republic of China ^[2]

Famotidine Drug Description

Famotidine classification

Digestive System Drugs> Acid and Gastric Mucosal Protection

Famotidine traits

This product is white or slightly yellow-white crystal, odorless and slightly bitter. Soluble in dimethylformamide or glacial acetic acid, difficult to dissolve in methanol, extremely difficult to dissolve in water, acetonitrile, absolute ethanol or acetone, and almost insoluble in chloroform or ether. Melting point 163-164 ° C.

Famotidine dosage form

1. Tablets: 10mg, 20mg, 40mg each;

2. Capsule: 20mg;

3. Powder: 10%;

4. Injection: 20mg (2ml).

Pharmacological effects of famotidine

Famotidine is a high-efficiency, long-acting guanidyl thiazole H2 receptor blocker. It has a high affinity for H2 receptors, and its mechanism of action is similar to that of cimetidine. Famotidine can effectively inhibit gastric acid secretion caused by basal gastric acid, nocturnal gastric acid, and food stimuli, and it can also inhibit gastric acid secretion caused by histamine and pentagastrin. It inhibits H2 receptors 20 times stronger than cimetidine and 7.5 times stronger than ranitidine. In addition, famotidine can also inhibit pepsin secretion. Famotidine has no anti-androgens and interferes with drug metabolism enzymes ^[3] .

Famotidine pharmacokinetics

Famotidine is rapidly absorbed, but incomplete, oral bioavailability is about 50%, and it is not affected by food. It takes effect about 1 hour after oral administration, and the blood concentration reaches a peak in 2 to 3 hours, and the duration of the effect is about 12 hours or more. Famotidine is widely distributed in the body, with high concentrations in the digestive tract, kidney, liver, submandibular gland and pancreas, but does not penetrate the placental barrier. The plasma protein binding rate is 15% to 20%. The half-life was 3h whether orally or intravenously, and the half-life was prolonged in patients with renal insufficiency. Famotidine is metabolized to S-oxides in the liver in a small amount, and is mostly excreted from the kidneys in the original form, with less bile excretion. Urinary excretion rates of the original drug within 24 hours after oral and intravenous administration were 35% to 44% and 88% to 91%, respectively. Famotidine is also excreted in milk, and its drug concentration is similar to plasma concentration. Famotidine does not inhibit liver drug metabolism enzymes, so it does not affect the metabolism of drugs such as theophylline, phenytoin, warfarin, and diazepam, nor does it affect the distribution of procainamide in vivo ^[3] .

Famotidine indications

For gastric and duodenal ulcers, anastomotic ulcers, reflux esophagitis, upper gastrointestinal bleeding (due to peptic ulcer, acute stress ulcer, hemorrhagic gastritis), Zhuo-Ai syndrome.

Famotidine dosage

1. (1) Active gastroduodenal ulcer: 20 mg each time, one morning and one night, or 40 mg once before bedtime, the course of treatment is 4 to 6 weeks. (2) Maintenance treatment or prevention of recurrence of duodenal ulcer: 20 mg per day, taken at bedtime. (3) Reflux esophagitis: Degree or Degree: 20 mg daily, divided into 2 times, taken after breakfast and dinner, and treated for 4-8 weeks; Degree or Degree: 40 mg daily, divided into 2 times, Take after breakfast and dinner for 4-8 weeks. (4) Zhuo-Ai syndrome: The initial dose is 20mg each time, once every 6 hours, and the dose can be adjusted accordingly according to the condition later.

2. Intravenous injection: 20mg each time, once every 12 hours.

3. Intravenous infusion: Dosage is the same as intravenous injection ^[3] .

Famotidine adverse reactions

1. A few patients may develop rash and urticaria.

2. Nervous / mental system: common headaches, dizziness, weakness, hallucinations, etc. If it occurs, symptoms can be controlled with haloperidol.

3. Digestive system: A small number of patients have dry mouth, nausea, vomiting, constipation and diarrhea, occasionally a slight increase in aminotransferase, rare abdominal fullness and lack of appetite.

4. Blood system: occasional leukopenia.

5. Cardiovascular system: Rare heart rate increase, blood pressure rise, etc.

6. Others: (1) Rare tinnitus, flushing of the face, irregular menstruation, etc .; (2) Famotidine reduces gastric acid and is beneficial to the growth and reproduction of bacteria in the stomach, so it may occur in the case of gastric reflux Infection ^[3] .

Famotidine contraindications

Use with caution in patients with renal failure or liver disease, patients with a history of drug allergies

Pregnant women should be used with caution, breastfeeding women should stop breastfeeding

The safety of children has not been established.

Tumors should be ruled out before administration.

Patients with liver and kidney dysfunction and infants and children should be used with caution. This product should be used only after gastric cancer has been ruled out.

Famotidine drug interactions

Probenecid can reduce the clearance of famotidine and increase the blood concentration of famotidine.

2. It can increase the bioavailability of cefbutin and increase its blood concentration.

3. When used in combination with midazolam, the lipid solubility of midazolam may increase due to an increase in gastric pH, thereby increasing the gastrointestinal absorption of the latter.

4. Can reduce theophylline metabolism and elimination, increase theophylline toxicity (such as nausea, vomiting, palpitations, seizures, etc.).

5. Combined with antacids (such as magnesium hydroxide, aluminum hydroxide, etc.), can reduce the absorption of famotidine.

6. Taking dirithromycin immediately after taking motidin can slightly increase the absorption of the latter. The clinical significance of this interaction is unknown.

7. Can reduce the absorption of cefpodoxime and reduce the efficacy of cefpodoxime.

8. Can reduce the absorption of cyclosporine and reduce the plasma concentration of cyclosporine.

9. Can reduce the absorption of deslavudine and reduce the efficacy of deslavudine.

10. It has an antagonistic effect when combined with torazoline, which can reduce the efficacy of torazoline.

11. When combined with itraconazole, ketoconazole and other drugs, the latter's efficacy can be reduced. The mechanism is that famotidine reduces gastric acid secretion, resulting in a decrease in gastrointestinal absorption of the latter.

12. The positive inotropic effect of nifedipine can be reversed, and its mechanism may be that famotidine reduces cardiac output and cardiac output per stroke.

13. Smoking can reduce the efficacy of famotidine ^[3] .

Famotidine storage

15-25 ° C, protected from light.

Famotidine precautions

1. (1) People with liver and kidney dysfunction; (2) Infants; (3) People with a history of drug allergy.

2. The dose of intravenous injection does not exceed 20 mg each time.

Famotidine poisoning

Famotidine (gasbuta) is an H2 receptor antagonist that is 30 to 100 times more potent than cimetidine. The peak was reached 2 to 3 hours after oral administration, and the half-life was about 3 hours. It is widely distributed in the body but does not penetrate the placental barrier and is mainly excreted from the kidneys. For gastric and duodenal ulcers, anastomotic ulcers, reflux esophagitis, upper gastrointestinal bleeding, etc. Patients with renal failure or liver disease, those with a history of drug allergies should be used with caution. The oral LD50 of mice and rats is> 8g / kg; the usual oral dose is 20mg, 2 / d.

Clinical manifestation

1. Less adverse reactions, the most common are headache, dizziness, constipation and diarrhea, and occasionally rash, urticaria, leukopenia, elevated transaminase, etc.

2. Toxicity see the related content of cimetidine, but less and light.

diagnosis

The main points of diagnosis of famotidine poisoning are:

There is a history of application of famotidine, and the above manifestations appear.

treatment

The main treatment points of famotidine poisoning are:

1. Drugs should be discontinued when rash and urticaria appear.

2. See the relevant content of cimetidine in the treatment of poisoning:

(1) General adverse reactions can disappear on their own.

(2) Liver and kidney function damage should be actively treated to protect liver and kidney function.

(3) In the case of severe arrhythmia, anti-arrhythmic drugs can be applied according to the type of arrhythmia.

(4) Symptoms of allergic reactions can be treated with antihistamines or glucocorticoids ^[4] .

Famotidine Expert Reviews

Famotidine is a histamine H2 receptor antagonist. Its acid-suppressing effect is 7 times stronger than ranitidine and more than 30 times stronger than cimetidine. The rate of duodenal ulcer healing is significantly improved. The drug does not inhibit the CYP450 enzyme, so there is no significant drug interaction. Since famotidine can mask the symptoms of gastric cancer, it should be confirmed as non-malignant before administration. Famotidine has a better effect on chronic urticaria. Measles disappears quickly after taking the drug, and there are fewer adverse reactions ^[3] .

Famotidine famotidine tablets

Indications: This product is used to alleviate stomach pain, heartburn (heartburn), and acid regurgitation caused by hyperacidity.

Dosage: Oral. 1 tablet for adults, 2 times a day. No more than 2 tablets in 24 hours.

Dosage form: tablet

Adverse reactions: 1. Circulatory system: Rarely increased pulse rate, increased blood pressure and facial flushing.

2. Digestive system: occasional liver dysfunction such as elevated transaminase. Rarely bloating, lack of appetite, constipation, diarrhea, soft stools, thirst, nausea, and vomiting.

3. Central nervous system: rare headaches, heavy head, and general weakness.

4. Allergic reactions: occasional rashes and urticaria. If allergies occur, the drug should be discontinued.

5. Others: Rare irregular menstruation, facial edema and tinnitus.

Contraindications: 1. Disable those with severe renal insufficiency.

2. Banned for pregnant and lactating women.

Note: 1. The product should not be used continuously for more than 7 days, and the symptoms have not been relieved. You should consult your doctor or pharmacist.

2. Consult your doctor or pharmacist for the dosage of children.

3. Patients with hepatic insufficiency and children should be used with caution.

4. This product is mainly excreted by the kidney. Patients with renal insufficiency should be used with caution.

5. If you take too much or have serious adverse reactions, you should see a doctor immediately.

6. Those who are allergic to this product are prohibited, and those with allergies should use it with caution.

7. It is forbidden to use this product when its properties are changed.

8. Keep this product out of the reach of children.

9. Children must use under adult supervision.

10. If you are using other medicines, please consult your physician or pharmacist before using this product.

Ingredients: The main ingredient of this product is famotidine.

Function category: This product is an antacid over-the-counter medicine.

Drug interactions: 1. Probenecid will inhibit the excretion of famotidine from the renal tubules. When used with this product, consult a physician.

2. This product should not be used in combination with other antacids. For example, antacids containing aluminum hydroxide and magnesium can reduce the bioavailability of famotidine and reduce its absorption and blood concentration.

3. This product has a slight effect on the pharmacokinetics of theophylline, warfarin, diazepam, and nifedipine, and you should consult a physician when using it at the same time.

4. Drug interactions may occur if used concurrently with other drugs, please consult your physician or pharmacist for details.

Pharmacological effects: This product is a histamine-H2 receptor blocker. It has obvious inhibitory effect on gastric acid secretion, and also can inhibit pepsin secretion, and has a certain protective effect on experimental ulcers in animals. The effect is about 1 hour after taking the medicine, and the effect can be maintained for more than 12 hours ^[5] .