Cimetidine

Registered South African indications:

• Heartburn
• Dyspepsia
• Hyperacidity
• Gastric and duodenal ulcers
• Reflux oesophagitis
• Zollinger-Ellison syndrome
• Conditions associated with gastric hypersecretion
• Haemorrhage of the upper gastrointestinal tract

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Hepatic impairment
• Elderly
• Cardiovascular disease
• Suspected malignancy
• Prolonged use
• Galactose intolerance
• Lapp lactase deficiency
• Glucose-galactose malabsorption

Forms avail. in SA and covered in this monograph: inj, tab

Active ulcer
-Active duodenal, benign gastric and stomal ulceration

• Oral (tab): 200-400mg, 6-8hrly, with meals and at bedtime; Treatment duration: 4 weeks
  OR
• Oral (tab): 800mg at bedtime
  OR 
• Oral (tab): 400mg, 12hrly in morning and at bedtime; Treatment duration: 4 weeks
• IV/IM: 200mg, 4-6hrly; Max: 2.4g
  OR
• IV: 400mg, as an infusion over 30-60min, 4-6hrly

Prophylaxis of recurrent ulcers

• Oral (tab): 400mg, 12-24hrly; Treatment duration: 1 year

Peptic oesophagitis

• Oral (tab): 400mg, 6hrly, taken with meals and at bedtime; Treatment duration: 12 weeks; Max: 1600mg/24hrs
  OR
• Oral (tab): 800mg at bedtime; Treatment duration: 12 weeks; Max: 1600mg/24hrs
  OR
• Oral (tab): 400mg, 12hrly in the morning and at bedtime; Treatment duration: 12 weeks; Max: 1600mg/24hrs
• IV/IM: 200mg, 4-6hrly; Max: 2.4g
  OR
• IV: 400mg, as an infusion over 30-60min, 4-6hrly

Zollinger-Ellison syndrome
High gastric secretion

• Oral (tab): 200mg, 8hrly with meals and 400mg at bedtime
  OR
• Oral (tab): 400mg, 6hrly with meals and at bedtime
• IV/IM: 200mg, 4-6hrly; Max: 2.4g
  OR
• IV: 400mg, as an infusion over 30-60min, 4-6hrly

High risk from haemorrhage of the upper gastrointestinal tract
- Due to hepatic failure 

• Oral (tab): 200-400mg, 8hrly with meals and 400mg at bedtime
  OR
• Oral (tab): 400mg, 6hrly with meals and at bedtime
• IV/IM: 200mg, 4-6hrly; Max: 2.4g
  OR
• IV: 400mg, as an infusion over 30-60min, 4-6hrly

Symptomatic relief of heartburn, dyspepsia, hyperacidity

• Oral (tab): 200mg, 6hrly with meals; Treatment duration: 14 days; Max dose: 800mg/24hrs

Continuous infusion rate should be 50-100mg/hr

Not established for use in children below 16 years

Pregnancy

• Caution; no evidence of risk in studies
• Although tests in animals and clinical evidence reveal no hazards from the administration of cimetidine during pregnancy, cimetidine does cross the placental barrier. The use of this medicine during pregnancy should be avoided unless considered essential

Breastfeeding

• Caution; not recommended
• Although tests in animals and clinical evidence reveal no hazards from the administration of cimetidine during breastfeeding, cimetidine is excreted in breast milk. The use of this medicine during breastfeeding should be avoided unless considered essential

Renal Impairment

• Caution; dose adjustment recommended

Hepatic Impairment

• Caution; no dose adjustment recommended

Elderly

• Caution; no dose adjustment recommended

Porphyria Information

• Not porphyrinogenic (NP)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Headache
• Dizziness
• Depression
• Confusional states
• Hallucinations
• Tiredness
• Confusional states

Cardiovascular Disorders

• Tachycardia
• Sinus bradycardia
• Heart block

Gastrointestinal Disorders

• Diarrhoea
• Pancreatitis

Hepatobiliary Disorders

• Hepatitis
• Increased serum transaminase levels 

Genitourinary Disorders

• Increases in plasma creatinine
• Interstitial nephritis
• Gynaecomastia 
• Reversible impotence
• Galactorrhoea

Musculoskeletal Disorders

• Myalgia
• Arthralgia

Skin and Subcutaneous Tissue Disorders

• Skin rashes
• Reversible alopecia 
• Hypersensitivity vasculitis

Immune, Blood and Lymphatic System Disorders

• Leukopenia
• Thrombocytopenia
• Aplastic anaemia
• Pancytopenia
• Agranulocytosis
• Anaphylaxis

• Non-steroidal anti-inflammatory drugs
• Phenytoin
• Theophylline
• Oral anticoagulants
• Phenytoin
• Theophylline
• Agents with a narrow therapeutic index
• Agents causing decreased blood cell counts
• Intravenous lidocaine
• CYP450 inhibitors
• Procainamide
• Metformin
• Ciclosporin 
• Tacrolimus
• Atazanavir
• Ketoconazole
• Itraconazole 
• Posaconazole
• Carmustine
• Fluorouracil
• Epirubicin
• Radiation
• Narcotic analgesics

• Endoscopy +/- biopsy
• Full blood count
• Renal function

Specific cases may require

• Prothrombin time

Cimetidine inhibits both the stimulated and basal secretion of gastric acid and reduces pepsin output. It competitively inhibits the action of histamine at the histamine H2 receptor and is thus a histamine H2 receptor antagonist.

Tablet 200mg

• Acidown (F.D.C. SA)
• Adco-Cimetidine (Adcock)
• Bio-Cimetidine (Biotech)
• Cimlok (Be-Tabs)
• Lenamet  (Pharmacare)
• Rolab-Cimetidine (Sandoz)
• Secadine (Xixia)

Tablet 400mg

• Adco-Cimetidine (Adcock)
• Bio-Cimetidine (Biotech)
• Cimlok (Be-Tabs)
• Hexamet (Sandoz)
• Lenamet  (Pharmacare)
• Secadine (Xixia)

Injection (per 2ml) 200mg

• Lenamet  (Pharmacare)
• Pharma-Q Cimetidine (Pharma Q)
• Sabax Cimetidine (Adcock)