Cimetidine 200mg Tablets
It is used to treat or prevent GI (gastrointestinal) ulcers.It is used to treat gastroesophageal reflux disease (GERD; acid reflux). It is used to treat heartburn and sour stomach.It is used to treat syndromes caused by lots of stomach acid.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Histamine H2-receptor antagonist
Pharmacologic Class
H2-receptor blocker
Pregnancy Category
Category B
FDA Approved
Aug 1977
DEA Schedule
Not Controlled
Overview
What is this medicine?
Cimetidine is a medicine that helps reduce the amount of acid your stomach makes. It's used to treat and prevent heartburn, indigestion, and stomach ulcers. It works by blocking a natural chemical in your body that tells your stomach to produce acid.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Take your medication with meals and at bedtime, or as instructed by your doctor.
It's essential to take your medication with food to help prevent stomach upset. However, do not take antacids at the same time as your medication, as this may interfere with its effectiveness. If you have any questions or concerns, be sure to discuss them with your doctor.
If you experience heartburn, take your medication 30 minutes before eating or drinking foods and liquids that trigger heartburn. This can help prevent discomfort and reduce symptoms.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry place, away from the bathroom. Keep all medications in a secure location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. Instead, check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore local drug take-back programs in your area.
Missing a Dose
If you take your medication on a regular schedule, take a missed dose as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
If you take your medication as needed, be sure to follow your doctor's instructions and do not take it more frequently than recommended.
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Take your medication with meals and at bedtime, or as instructed by your doctor.
It's essential to take your medication with food to help prevent stomach upset. However, do not take antacids at the same time as your medication, as this may interfere with its effectiveness. If you have any questions or concerns, be sure to discuss them with your doctor.
If you experience heartburn, take your medication 30 minutes before eating or drinking foods and liquids that trigger heartburn. This can help prevent discomfort and reduce symptoms.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry place, away from the bathroom. Keep all medications in a secure location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. Instead, check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore local drug take-back programs in your area.
Missing a Dose
If you take your medication on a regular schedule, take a missed dose as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
If you take your medication as needed, be sure to follow your doctor's instructions and do not take it more frequently than recommended.
Lifestyle & Tips
- Avoid foods and drinks that trigger your heartburn or indigestion (e.g., spicy foods, fatty foods, caffeine, alcohol, carbonated beverages).
- Eat smaller, more frequent meals.
- Avoid eating close to bedtime (within 2-3 hours).
- Elevate the head of your bed if you experience nighttime heartburn.
- Quit smoking, as it can worsen acid reflux.
- Maintain a healthy weight.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
For heartburn (OTC): 200 mg with a glass of water as needed, up to twice daily. For active duodenal ulcer: 800 mg once daily at bedtime or 400 mg twice daily or 300 mg four times daily. For GERD: 400 mg twice daily.
Dose Range:
200 - 2400 mg
Condition-Specific Dosing:
activeDuodenalUlcer:
800 mg once daily at bedtime or 400 mg twice daily or 300 mg four times daily for 4-8 weeks.
gastricUlcer:
800 mg once daily at bedtime or 300 mg four times daily for 6-8 weeks.
GERD:
400 mg twice daily for 6-12 weeks.
pathologicalHypersecretoryConditions (e.g., Zollinger-Ellison Syndrome):
300 mg four times daily, may increase to 2400 mg/day.
heartburnPrevention (OTC):
200 mg 30 minutes before eating food or drinking beverages that cause heartburn, up to twice daily.
Pediatric Dosing
Neonatal:
Not established (limited data, use with caution).
Infant:
Not established (limited data, use with caution).
Child:
Not routinely recommended; if used, typically 20-40 mg/kg/day divided every 6-12 hours (max 2400 mg/day).
Adolescent:
Similar to adult dosing for specific indications, but generally not first-line.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment typically needed for CrCl > 50 mL/min.
Moderate:
Reduce dose by 50% for CrCl 30-50 mL/min (e.g., 300 mg every 12 hours).
Severe:
Reduce dose significantly for CrCl < 30 mL/min (e.g., 300 mg every 24 hours).
Dialysis:
Administer after dialysis; supplemental dose may be needed. Dosage should be individualized based on clinical response and tolerance.
Hepatic Impairment:
Mild:
No specific adjustment recommended.
Moderate:
No specific adjustment recommended, but use with caution due to potential for increased CNS effects.
Severe:
No specific adjustment recommended, but use with caution due to potential for increased CNS effects and altered drug metabolism.
Pharmacology
Mechanism of Action
Cimetidine is a histamine H2-receptor antagonist. It competitively inhibits the binding of histamine to H2 receptors on the gastric parietal cells, leading to a reduction in gastric acid secretion (both basal and stimulated). This reduces the volume of gastric acid and its hydrogen ion concentration.
Pharmacokinetics
Absorption:
Bioavailability:
60-70% (oral)
Tmax:
1-2 hours
FoodEffect:
Food may slightly delay absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
0.8 L/kg
ProteinBinding:
13-25%
CnssPenetration:
Limited, but can cross the blood-brain barrier, especially with high doses or in patients with renal impairment, leading to CNS side effects.
Elimination:
HalfLife:
Approximately 2 hours (in patients with normal renal function)
Clearance:
Approximately 300-500 mL/min (renal clearance is predominant)
ExcretionRoute:
Renal (primarily unchanged drug)
Unchanged:
Approximately 48% (oral dose) to 75% (IV dose) excreted unchanged in urine.
Pharmacodynamics
OnsetOfAction:
Within 30 minutes
PeakEffect:
1-2 hours
DurationOfAction:
4-6 hours (single dose), up to 10-12 hours (with repeated dosing or higher doses)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Confusion
Agitation
Mood changes
Hallucinations (seeing or hearing things that are not there)
Enlarged breasts
Liver problems, which can be rare but potentially deadly. Warning signs may include:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to contact your doctor or seek medical help if you have any symptoms that bother you or persist. Not all possible side effects are listed here. If you have questions or concerns about side effects, consult your doctor.
Reporting Side Effects
To report side effects, you can:
Call your doctor for medical advice
Contact the FDA at 1-800-332-1088
Visit the FDA's MedWatch website at https://www.fda.gov/medwatch
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Confusion
Agitation
Mood changes
Hallucinations (seeing or hearing things that are not there)
Enlarged breasts
Liver problems, which can be rare but potentially deadly. Warning signs may include:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to contact your doctor or seek medical help if you have any symptoms that bother you or persist. Not all possible side effects are listed here. If you have questions or concerns about side effects, consult your doctor.
Reporting Side Effects
To report side effects, you can:
Call your doctor for medical advice
Contact the FDA at 1-800-332-1088
Visit the FDA's MedWatch website at https://www.fda.gov/medwatch
Seek Immediate Medical Attention If You Experience:
- Severe or persistent stomach pain
- Difficulty or pain when swallowing
- Vomiting blood or material that looks like coffee grounds
- Black, tarry stools (sign of bleeding in the stomach or intestines)
- Unexplained weight loss
- New or worsening confusion, especially in older adults
- Unusual tiredness or weakness
- Yellowing of the skin or eyes (jaundice)
- Unusual bruising or bleeding
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking dofetilide, as this may interact with the medication.
If you are breast-feeding, as you should not breast-feed while taking this medication.
Additionally, to ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
Your existing health problems
This information will help your doctor determine if it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you are currently taking dofetilide, as this may interact with the medication.
If you are breast-feeding, as you should not breast-feed while taking this medication.
Additionally, to ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
Your existing health problems
This information will help your doctor determine if it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you experience any of the following symptoms, contact your doctor immediately: throat pain, chest pain, severe abdominal pain, difficulty swallowing, or signs of a bleeding ulcer, such as black, tarry, or bloody stools, vomiting blood, or vomit that resembles coffee grounds, as these may indicate a more serious health issue.
When taking this medication, it is crucial to coordinate with other medications you are using, as they may need to be taken at a different time. Consult with your doctor or pharmacist to determine the best schedule for taking your medications.
If you are 50 years or older, exercise caution when using this medication, and discuss any concerns with your doctor. Additionally, if you are pregnant or planning to become pregnant, inform your doctor, as you will need to discuss the potential benefits and risks of using this medication during pregnancy.
When taking this medication, it is crucial to coordinate with other medications you are using, as they may need to be taken at a different time. Consult with your doctor or pharmacist to determine the best schedule for taking your medications.
If you are 50 years or older, exercise caution when using this medication, and discuss any concerns with your doctor. Additionally, if you are pregnant or planning to become pregnant, inform your doctor, as you will need to discuss the potential benefits and risks of using this medication during pregnancy.
Overdose Information
Overdose Symptoms:
- Respiratory depression
- Tachycardia
- Arrhythmias
- CNS depression (e.g., sedation, confusion, disorientation, slurred speech)
- Seizures (rare)
- Renal failure (rare)
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is generally supportive and symptomatic. Gastric lavage and activated charcoal may be considered if ingestion is recent.
Drug Interactions
Major Interactions
- Dofetilide (increased dofetilide levels, risk of QT prolongation)
- Phenytoin (increased phenytoin levels, toxicity)
- Theophylline (increased theophylline levels, toxicity)
- Warfarin (increased anticoagulant effect, bleeding risk)
- Lidocaine (increased lidocaine levels, toxicity)
- Tricyclic antidepressants (e.g., imipramine, desipramine; increased TCA levels, toxicity)
- Metformin (increased metformin levels, risk of lactic acidosis)
Moderate Interactions
- Calcium channel blockers (e.g., nifedipine, diltiazem; increased levels)
- Benzodiazepines (e.g., diazepam, chlordiazepoxide; increased levels, prolonged sedation)
- Beta-blockers (e.g., propranolol, metoprolol; increased levels)
- Cyclosporine (increased cyclosporine levels, nephrotoxicity)
- Tacrolimus (increased tacrolimus levels)
- Ketoconazole, Itraconazole (decreased absorption due to increased gastric pH)
- Iron salts (decreased absorption due to increased gastric pH)
- Atazanavir (decreased absorption due to increased gastric pH)
- Quinine (increased quinine levels)
- Procainamide (increased procainamide levels)
Minor Interactions
- Alcohol (may increase blood alcohol levels slightly)
- Sucralfate (may reduce cimetidine absorption if given concurrently; separate by 2 hours)
Monitoring
Baseline Monitoring
Renal function (BUN, creatinine)
Rationale: Cimetidine is primarily renally eliminated; dose adjustment is necessary in renal impairment.
Timing: Prior to initiation of therapy, especially in elderly or patients with known renal issues.
Routine Monitoring
Clinical symptoms (e.g., heartburn, ulcer pain)
Frequency: Daily to weekly, as needed
Target: Resolution or significant improvement of symptoms
Action Threshold: Persistent or worsening symptoms may indicate inadequate dosing or alternative diagnosis.
Renal function (BUN, creatinine)
Frequency: Periodically, especially in elderly or those with pre-existing renal impairment or on long-term therapy.
Target: Within patient's baseline or normal limits
Action Threshold: Significant increase in BUN/creatinine may necessitate dose adjustment.
Liver function tests (ALT, AST, bilirubin)
Frequency: Rarely, only if clinically indicated or with long-term high-dose therapy.
Target: Within normal limits
Action Threshold: Significant elevation may warrant discontinuation.
Complete Blood Count (CBC)
Frequency: Rarely, only if clinically indicated or with long-term high-dose therapy (e.g., >1 year).
Target: Within normal limits
Action Threshold: Significant changes (e.g., leukopenia, thrombocytopenia) may warrant discontinuation.
Symptom Monitoring
- Persistent or worsening abdominal pain
- Difficulty swallowing
- Vomiting blood or material that looks like coffee grounds
- Black, tarry stools
- Unexplained weight loss
- New or worsening confusion, especially in elderly or renally impaired patients
- Unusual bleeding or bruising
- Breast tenderness or enlargement (gynecomastia)
Special Patient Groups
Pregnancy
Cimetidine is classified as Pregnancy Category B. Animal studies have not shown harm to the fetus, and there are no adequate and well-controlled studies in pregnant women. It is generally considered safe for use during pregnancy when clearly needed, but use should be weighed against potential benefits.
Trimester-Specific Risks:
First Trimester:
Low risk based on available data.
Second Trimester:
Low risk based on available data.
Third Trimester:
Low risk based on available data.
Lactation
Cimetidine is excreted into breast milk. The American Academy of Pediatrics considers it compatible with breastfeeding (L2 - Likely Compatible). Monitor breastfed infants for potential side effects such as CNS effects (irritability, drowsiness) or changes in feeding patterns, though these are rare.
Infant Risk:
Low risk; monitor for potential side effects.
Pediatric Use
Not routinely recommended for children due to limited data and availability of other agents. If used, dosing must be carefully calculated based on weight and indication. CNS effects may be more pronounced in younger children.
Geriatric Use
Elderly patients are more susceptible to CNS side effects (e.g., confusion, disorientation, hallucinations) due to reduced renal clearance and potential for higher plasma concentrations. Dose adjustments are often necessary based on renal function. Use with caution and start with lower doses.
Clinical Information
Clinical Pearls
- Cimetidine is a potent inhibitor of several CYP450 enzymes (especially CYP1A2, 2C9, 2D6, 3A4), leading to numerous significant drug interactions. Always review patient's medication list for potential interactions.
- While available OTC for heartburn, higher prescription doses are used for ulcers and GERD.
- Gynecomastia and impotence can occur with long-term, high-dose use, though less common with typical OTC doses.
- Confusion and other CNS effects are more common in elderly patients or those with renal impairment.
- For OTC use, advise patients not to take for more than 14 days without consulting a doctor.
Alternative Therapies
- Other H2-receptor antagonists (e.g., Ranitidine, Famotidine, Nizatidine)
- Proton pump inhibitors (PPIs) (e.g., Omeprazole, Esomeprazole, Lansoprazole, Pantoprazole, Rabeprazole)
- Antacids (e.g., Calcium carbonate, Aluminum hydroxide/Magnesium hydroxide)
- Sucralfate (for ulcer treatment)
- Prokinetics (e.g., Metoclopramide, for motility issues)
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (200mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Preferred Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication, including the amount taken and the time it happened, to ensure you receive the best possible care.