Patient Medication Information: uses, side effects, how to take - Cimetidine
What is CIMETIDINE used for?
CIMETIDINE is used in adults to:
- treat active sores in the upper part of the intestine (duodenum ulcers) and stomach (gastric ulcers).
- prevent intestinal or stomach ulcers from coming back after they have healed.
- treat Gastroesophageal Reflux Disease (GERD). This is a condition where the acid from the stomach persistently escapes into the food pipe causing pain, inflammation and heartburn.
treat and relieve abnormal excessive acid secretion in the stomach caused by:
- a tumour in the pancreas (Zollinger-Ellison syndrome).
- too many mast cells building up in your body (systemic mastocytosis)
- tumours in the parathyroid, pituitary glands and pancreas (multiple endocrine adenomas)
- treat and prevent lesions (ulcers, erosions) caused by non-steroidal anti-inflammatory drugs (NSAIDs) and gastrointestinal symptoms such as nausea, vomiting, abdominal pain, indigestion and chest pain.
CIMETIDINE is used in children (16 to 18 years of age) with cystic fibrosis to:
- manage their gastrointestinal symptoms. Cystic fibrosis is an inherited life-threatening disorder that damages the lungs and digestive tract.
How does CIMETIDINE work?
CIMETIDINE belongs to a group of medicines called Histamine H2 receptor antagonists (H2 blockers). It works by reducing the amount of acid produced by your stomach.
What are the ingredients in CIMETIDINE?
Medicinal ingredients: cimetidine
Non-medicinal ingredients: carnauba wax, colloidal silicon dioxide, croscarmellose sodium, D&C Yellow No. 10 Lake 16%, ferric ferrous oxide, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol and titanium dioxide.
CIMETIDINE comes in the following dosage forms:
Tablets: 200 mg, 300 mg, 400 mg, 600 mg and 800 mg.
Do not use CIMETIDINE if:
- you are allergic to cimetidine or to any other ingredients in CIMETIDINE or its packaging.
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take CIMETIDINE. Talk about any health conditions or problems you may have, including if you:
- are middle-aged or over, with new or recently changed indigestion symptoms (e.g. stomach pain or discomfort, heartburn). Your healthcare professional will check if the cause of your symptoms is stomach cancer before starting treatment with CIMETIDINE.
- have kidney problems.
- are undergoing hemodialysis treatment.
Other warnings you should know about:
Pregnancy: CIMETIDINE is not recommended during pregnancy. If you discover that you are pregnant while taking CIMETIDINE, tell your healthcare professional right away. Only take CIMETIDINE during pregnancy if your healthcare professional has decided it is right for you and your baby.
Breastfeeding: CIMETIDINE passes into breast milk. CIMETIDINE is not recommended while breastfeeding. Only take CIMETIDINE while breastfeeding if your healthcare professional has decided it is right for you and your baby.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
The following may interact with CIMETIDINE:
- chlordiazepoxide, a medicine used to treat anxiety and alcohol withdrawal.
- medicines used to prevent seizures (fits), such as phenytoin and diazepam.
- lidocaine, a medicine used to numb an area of your body to help reduce pain or discomfort caused by a procedure.
- medicines used to treat high blood pressure, such as propranolol and nifedipine.
- non-steroidal anti-inflammatory drugs (NSAIDs), used to reduce pain and inflammation. This includes acetylsalicylic acid (ASA, or aspirin), ibuprofen, naproxen, and diclofenac.
- theophylline, a medicine used to treat asthma and other lung diseases.
- blood thinners, such as warfarin.
How to take CIMETIDINE:
- Take CIMETIDINE exactly as your healthcare professional tells you.
- Continue taking CIMETIDINE for the prescribed length of treatment even if you are feeling better. Stopping treatment too early may delay the healing process.
- Your healthcare professional may ask you to take other antacids during your treatment with CIMETIDINE.
Usual dose:
The dose of CIMETIDINE prescribed to you will depend on your condition. Your healthcare professional may change your dose depending on your response to CIMETIDINE.
To treat active intestinal or stomach ulcers: The recommended adult dose is 800 to 1200 mg per day. It may be given as follows:
- 800 mg once daily at bedtime; or
- 600 mg twice daily, at breakfast and bedtime; or
300 mg four times daily with meals and at bedtime.
Take CIMETIDINE for at least 4 weeks if you have an intestinal ulcer or 6 weeks for a stomach ulcer unless otherwise instructed by your healthcare professional.
- To prevent intestinal or stomach ulcers from coming back: The usual adult dose is 400 mg once daily at bedtime, or 300 mg twice daily, at breakfast and bedtime. Take CIMETIDINE for at least 6 to 12 months.
To treat GERD: The recommended adult dose is 1200 mg per day. It may be given as follows:
- 800 mg once daily at bedtime; or
- 600 mg twice daily, at breakfast and bedtime; or
- 300 mg four times daily with meals and at bedtime.
Take CIMETIDINE for 8 to 12 weeks.
- To treat and relieve abnormal excessive acid secretion in the stomach caused by tumours or mast cell buildup: The recommended adult dosage is 300 mg four times a day, with meals and at bedtime. Your healthcare professional will increase the dose based on your condition if necessary. The maximum dose is 2400 mg per day.
- To treat and prevent lesions caused by NSAIDs and gastrointestinal symptoms: The recommended adult dose is 800 mg once daily at bedtime or 400 mg twice daily, for 8 weeks. After the 8-week period, the recommended dose is 400 mg once daily at bedtime.
- To manage gastrointestinal symptoms in children with cystic fibrosis: Your healthcare professional will decide the right dose of CIMETIDINE for your child depending on their body weight.
Overdose:
| If you think you, or a person you are caring for, have taken too much CIMETIDINE, contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms. |
Missed Dose:
If you forget or miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the next dose as scheduled. Do not double the dose to make up for a missed dose.
What are possible side effects from using CIMETIDINE?
These are not all the possible side effects you may have when taking CIMETIDINE. If you experience any side effects not listed here, tell your healthcare professional.
Side effects may include:
- diarrhea
- feeling tired
- dizziness
- hair loss
- joint pain
- muscle pain
- breast growth in males
- impotence (inability to get or keep an erection). This side effect may be reversible after withdrawing the medicine. If you experience this side effect, continue taking CIMETIDINE and consult your healthcare professional. They may give you a different dose or prescribe you a different medicine.
CIMETIDINE can cause abnormal blood test results. Your healthcare professional will decide when to perform blood tests and will interpret the results.
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
|---|---|---|---|
| Only if severe | In all cases | ||
| RARE | |||
| Abnormally slow or fast heartbeat | √ | ||
| Fever | √ | ||
| Heart block (disturbances in the electrical system of the heart): slow or irregular heartbeat, shortness of breath, light-headedness, fainting, pain or discomfort in the chest, difficulty doing exercises | √ | ||
| Hepatitis (inflammation of the liver): abdominal pain and swelling, fatigue, fever, nausea, vomiting, itchiness, light coloured stool, loss of appetite, dark urine, trouble thinking clearly, yellowing of the eyes and skin | √ | ||
| Hypersensitivity vasculitis (allergic reaction leading to inflammation and damage to blood vessels, mainly in the skin): skin redness, red, brown or purple-coloured spots and patches on the skin, blistering of the skin or scabbing, swelling of the arms and legs, itchiness | √ | ||
| Inability to pass urine or to empty the bladder | √ | ||
| Nephritis (inflammation of the kidney): decreased appetite, difficulty breathing, fatigue, frequent urination, itchiness, nausea, vomiting | √ | ||
| Pancreatitis (inflammation of the pancreas): upper abdominal pain, fever, rapid heart beat, nausea, vomiting, tenderness when touching the abdomen | √ | ||
| Polymyositis (inflammatory muscle disease): muscle weakness, difficulty to climb stairs, rise from a seated position, lift objects or | √ | ||
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help |
|---|
| Only if severe | In all cases | ||
|---|---|---|---|
| reach overhead | |||
| Severe allergic reactions: sudden wheeziness and chest pain or tightness; or swelling of eyelids, face, lips, tongue or throat, trouble breathing, collapse | √ | ||
| Worsening of arthritis: joint pain and stiffness | √ | ||
| UNKNOWN FREQUENCY | |||
Anemias:
| √ | ||
| Cholestasis in children (decrease in bile flow from the liver): jaundice (yellowing of the skin or whites of eyes), dark urine, light coloured stools | √ | ||
| Leukopenia / Agranulocytosis (decrease in white blood cells): frequent infection, fatigue, fever, aches, pains and flu-like symptoms | √ | ||
Mental health problems:
| √ | ||
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help |
|---|
| Only if severe | In all cases | ||
|---|---|---|---|
| |||
| Neurotoxicity in children (damage to the nervous system): agitation, blurred vision, confusion, convulsions, difficulty speaking, dizziness, hallucinations, headache, impaired thinking, loss of control of body movements, memory loss, mental status changes, nervousness, numbness and tingling, vision loss, muscle weakness, seizures | √ | ||
| Pancytopenia (decrease in red and white blood cells and platelets): paleness of the skin, fatigue, rapid heart rate, shortness of breath, fever, and symptoms of infection such as cough, bruising easily and heavy bleeding | √ | ||
| Serious Skin Reactions (including Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis and generalized exfoliative erythroderma): redness, blistering and/or peeling of the skin, including the inside of the lips, eyes, mouth, nasal passages or genitals, swelling of the skin or serious skin rashes, raised red or purple skin patches, possibly with crust in the center, itchiness, burning sensation, can be accompanied with fever, chills, headache, cough, body aches or swollen glands, generally feeling unwell | √ | ||
| Thrombocytopenia (low blood platelets): bruising or bleeding for longer than usual if you hurt yourself, fatigue and weakness | √ | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting Side Effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice. |
Storage:
- Store at room temperature (15°C to 30°C).
- If your healthcare professional tells you to stop taking CIMETIDINE, please return any leftover medicine to your pharmacist. CIMETIDINE should never be disposed of in your household trash.
- Keep out of reach and sight of children.
If you want more information about CIMETIDINE:
- Talk to your healthcare professional
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html); the manufacturer’s website (https://www.aapharma.ca/en/), or by calling 1-877-998-9097.