Cimetidine

Presented By:

Ameer

Hamza

ShaheedSubmitted To:

Sir Irfan Hamid

Drug name : Cimetidin

Pharmacological class: Histamine H2 Antagonists

Enzyme Inhibitors

Therapeutic class: Anti-Ulcer Agents

Cimetidine

GUANIDINE, N-CYANO-N'-METHYL-N''-[ 2-[[(5-METHYL-1H-IMIDAZOL- 4-YL)METHYL]THIO]ETHYL]

Chemical name:

Chemical structure:

CIMETIDINE CONTAINS AN IMIDAZOLE RING, AND IS CHEMICALLY RELATED TO HISTAMINE.

(HTTP://WWW.DRUGS.COM/PRO/CIMETIDINE.HTML)

EMPIRICAL FORMULA: C10H16N6S

PREGNANCY CATEGORY: B

Physical properties:

SOLUBILITY: SPRINGLY SOLUBLE IN WATER, BUT SOLUBLE IN ALCOHOL .

MELTING POINT: 139 – 144 C

Colour: White or off white crystalline powder.

Odour: Unpleasant odour.

Pharmcodynamics

CIMETIDINE IS A HISTAMINE H2-RECEPTOR ANTAGONIST.IT REDUCES GASTRIC SECREATION.

CIMETIDINE INHIBITS MANY OF THE ISOENZYMES OF THE HEPATIC CYP450 ENZYME SYSTEM.

Cimetidine binds to an H2-receptor located on the basolateral membrane of the gastric parietal cell, blocking histamine effects. This competitive inhibition results in reduced gastric acid secretion and a reduction in gastric volume and acidity.

Pharmacokinetics

Metabolism: Liver, inhibit microsomal enzymes

Metabolites: Cimetidine sulfoxide, 5-hydroxymethyl derivative (inactive met) (lynn wecker page # 198)

Bioavailability: PO: 60-70% (undergoes minimal 1st pass metabolism)

Protein Bound: 15-20%

Half life: 2 hours

Absorption : Oral/I.V 60 % 

Excretion:

Urine: 48-75% Feces: 2-3%

Enzymes inhibited:

CYP1A2

CYP2D6

CYP3A4

Clinical Uses & therapeutic Indication

Peptic Ulcer:

Peptic ulcers are sores in the lining of the stomach or duodenum.

Causes : H.pylori bacteria .

Regular use of pain relievers. NSAID,s

(aspirin, ibuprofen , naproxen , ketoprofen)

(This information taken from book Medical pharmacology by Padmaja Udaykumar)

(page #317))

Gastroesophageal reflux disease

Reflux Oesophagitis :Acid from the stomach leaks up into the gullet

(oesophagus)

This information taken from(

http://www.patient.co.uk/health/Acid-Reflux-and-Oesophagitis.htm

)

Zollinger-Ellison syndrome:

The exact cause of Zollinger-Ellison syndrome remains unknown.

Zollinger-Ellison syndrome are made up of cells (gastrinomas) that secrete large amounts of gastrin, which in turn causes the stomach to produce far too much acid.

(http://www.mayoclinic.com/health/zollinger-ellison-syndrome/DS00461/DSECTION=causes)

Acid related dyspepsia:

Dyspepsia is sometimes called indigestion.

Discomfort that causes persistent pain or fullness in the upper abdomen, soon after the meal starts.

(http://www.medindia.net/patients/patientinfo/indigestion.htm)

Stress ulcer:

Stress can contribute to the development of many diseases .This includes stomach, or peptic, ulcers.

 (http://www.livestrong.com/article/174015-a-stomach-ulcer-from-stress/#ixzz2F8KFZBmc )

Dosages

• 800 mg/D• At bed time

• 400 mg q.i.d upto 12 weeks

• 200 mg q.i.d • With meal at

bed time

• 200 mg t.d.s• With meal at

bed time

Peptic Ulcer

Reflux oesophagitis

Acid related dyspeps

ia

Zollinger-Ellison

syndrome

This information taken from book Pharmaguid page # 38

Drug Interactions

Cimetidine

These information taken from,

Pharmaguide page #39.

http://www.merckmanuals.com/professional/clinical_pharmacology/pharmacokinetics/drug_metabolism.html

http://www.aafp.org/afp/2007/0801/p391.html

Common side effects:

Headache.Constipation.Confusion.Somnolence.

Rare but dangerous side effect:Decrease libidoDecrease sperm countImpotence Gynecomastia

(These side effects associated with

high dose of cimetidine)

Lynn wecker page # 200

Brand names for Cimetidin

e

B.N: Cimet

M.N: Ferozsons

Tab.: 400 mg

B.N: Normacid

M.N: Wilson

Tab.: 400 , 800 mg

B.N: Bacimet

M.N: Davis pharma

Tab.: 200 , 400 mg

Cimetidine

Any Question ?