Cimetidine Oral Liq 300mg/5ml
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
Antiulcer agents
Pharmacologic Class
H2-receptor antagonists
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 conditions like heartburn, ulcers, and acid reflux.
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 avoid taking antacids at the same time as your medication. If you have any questions or concerns, discuss them with your doctor. To help prevent heartburn, take your medication 30 minutes before consuming foods or drinks that trigger heartburn.
When taking the liquid form of this medication, measure your dose accurately using the measuring device provided. If you don't have a measuring device, ask your pharmacist for one.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, ask your pharmacist. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you take your medication on a regular schedule, take the 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, do not take it more frequently than directed by your doctor.
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 avoid taking antacids at the same time as your medication. If you have any questions or concerns, discuss them with your doctor. To help prevent heartburn, take your medication 30 minutes before consuming foods or drinks that trigger heartburn.
When taking the liquid form of this medication, measure your dose accurately using the measuring device provided. If you don't have a measuring device, ask your pharmacist for one.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. If you're unsure about the best way to dispose of your medication, ask your pharmacist. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you take your medication on a regular schedule, take the 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, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Avoid foods and drinks that trigger your symptoms (e.g., spicy foods, fatty foods, caffeine, alcohol, chocolate, peppermint).
- Eat smaller, more frequent meals instead of large ones.
- Avoid lying down immediately after eating; wait at least 2-3 hours.
- Elevate the head of your bed if you experience nighttime heartburn.
- Avoid smoking, as it can worsen acid reflux.
- Do not take antacids within 1 hour of taking cimetidine, as they can reduce its absorption. Separate by at least 1 hour.
- Take exactly as prescribed, even if you feel better. Do not stop taking it without consulting your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
For active duodenal ulcer: 800 mg once daily at bedtime OR 300 mg four times daily with meals and at bedtime. For maintenance: 400 mg once daily at bedtime. For GERD: 800 mg twice daily or 400 mg four times daily. For Zollinger-Ellison Syndrome: 300 mg four times daily, may increase up to 2400 mg/day in divided doses.
Dose Range:
300 - 2400 mg
Condition-Specific Dosing:
active_duodenal_ulcer:
800 mg PO once daily at bedtime OR 300 mg PO QID with meals and at bedtime for up to 8 weeks.
maintenance_duodenal_ulcer:
400 mg PO once daily at bedtime.
gastric_ulcer:
300 mg PO QID with meals and at bedtime for up to 6 weeks.
GERD:
800 mg PO BID or 400 mg PO QID for up to 12 weeks.
Zollinger_Ellison_Syndrome:
300 mg PO QID, may increase up to 2400 mg/day in divided doses.
Pediatric Dosing
Neonatal:
Not established (use with caution, typically 5-10 mg/kg/day divided Q8-12H, under specialist guidance).
Infant:
Not established (use with caution, typically 10-20 mg/kg/day divided Q6-12H, under specialist guidance).
Child:
20-40 mg/kg/day PO divided every 6-8 hours (max 2400 mg/day).
Adolescent:
Similar to adult dosing, typically 20-40 mg/kg/day PO divided every 6-8 hours (max 2400 mg/day) or adult doses for specific indications.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed for CrCl > 50 mL/min.
Moderate:
For CrCl 30-50 mL/min: Consider 300 mg every 8-12 hours.
Severe:
For CrCl < 30 mL/min: 300 mg every 12 hours. For CrCl < 15 mL/min: 300 mg every 24 hours.
Dialysis:
Administer after dialysis. Hemodialysis removes cimetidine; supplemental dose may be needed. Peritoneal dialysis removes minimal amounts.
Confidence:
Medium
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed, but use with caution due to potential for increased half-life and CNS effects in severe impairment.
Severe:
No specific adjustment needed, but monitor for increased adverse effects, especially CNS effects, due to reduced clearance. Consider lower doses if severe hepatic and renal impairment coexist.
Confidence:
Medium
Pharmacology
Mechanism of Action
Cimetidine is a histamine H2-receptor antagonist. It reversibly blocks the binding of histamine to the H2-receptors on the gastric parietal cells, leading to a reduction in both basal and stimulated gastric acid secretion. This results in decreased gastric volume and acidity.
Pharmacokinetics
Absorption:
Bioavailability:
60-70%
Tmax:
1-1.5 hours
FoodEffect:
Food slightly delays absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
0.8 L/kg
ProteinBinding:
13-25%
CnssPenetration:
Limited (can cross BBB, especially with high doses or renal impairment, leading to CNS effects)
Elimination:
HalfLife:
2-3 hours (prolonged in renal impairment to 3.5-12 hours)
Clearance:
Approximately 300-500 mL/min
ExcretionRoute:
Renal (primary), Fecal (minor)
Unchanged:
50-80% (renal)
Pharmacodynamics
OnsetOfAction:
Within 30 minutes
PeakEffect:
1-2 hours
DurationOfAction:
4-6 hours (acid suppression)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help 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 attention 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. Be aware of signs such as:
+ 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. This is not an exhaustive list of potential side effects. If you have questions or concerns, consult your doctor.
Reporting Side Effects
If you experience any side effects, you can report them to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor is also available to provide medical advice and guidance on managing side effects.
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 attention 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. Be aware of signs such as:
+ 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. This is not an exhaustive list of potential side effects. If you have questions or concerns, consult your doctor.
Reporting Side Effects
If you experience any side effects, you can report them to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor is also available to provide medical advice and guidance on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Severe stomach pain or cramping
- Black, tarry stools or blood in your stool
- Vomit that looks like coffee grounds
- Unusual tiredness or weakness
- Yellowing of the skin or eyes (jaundice)
- Dark urine
- Confusion, hallucinations, or unusual changes in mood or behavior (especially in older adults or those with kidney problems)
- Unexplained breast enlargement (in men) or changes in sexual desire/ability (rare, with long-term high doses)
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 allergic reaction you experienced, including any symptoms that occurred.
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 discuss all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
with your doctor and pharmacist. This will help determine if it is safe 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 allergic reaction you experienced, including any symptoms that occurred.
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 discuss all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
with your doctor and pharmacist. This will help determine if it is safe 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 drug, 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 drug, 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 or bradycardia
- CNS depression (e.g., sedation, lethargy, disorientation, confusion)
- Seizures
- Slurred speech
- Ataxia
What to Do:
Seek immediate medical attention. Call 911 or your local poison control center (1-800-222-1222 in the US).
Drug Interactions
Major Interactions
- Warfarin (increased INR, bleeding risk)
- Phenytoin (increased phenytoin levels, toxicity)
- Theophylline (increased theophylline levels, toxicity)
- Lidocaine (increased lidocaine levels, toxicity)
- Procainamide (increased procainamide levels, toxicity)
- Metformin (increased metformin levels, lactic acidosis risk)
- Dofetilide (increased dofetilide levels, QT prolongation, Torsades de Pointes)
- Flecainide (increased flecainide levels)
- Quinidine (increased quinidine levels)
- Tricyclic antidepressants (e.g., imipramine, amitriptyline) (increased TCA levels)
Moderate Interactions
- Drugs requiring acidic gastric pH for absorption (e.g., ketoconazole, itraconazole, atazanavir, iron salts, calcium carbonate) (decreased absorption)
- Antacids (decreased cimetidine absorption if given concurrently; separate administration by at least 1 hour)
- Sucralfate (decreased cimetidine absorption; administer cimetidine at least 2 hours before sucralfate)
- Benzodiazepines (e.g., diazepam, chlordiazepoxide) (increased benzodiazepine levels, enhanced sedation)
- Calcium channel blockers (e.g., nifedipine, diltiazem) (increased CCB levels)
- Beta-blockers (e.g., propranolol, metoprolol) (increased beta-blocker levels)
- Cyclosporine (increased cyclosporine levels)
- Tacrolimus (increased tacrolimus levels)
- Sildenafil (increased sildenafil levels)
- Clozapine (increased clozapine levels)
Minor Interactions
- Alcohol (may increase blood alcohol levels slightly)
- Caffeine (decreased caffeine clearance)
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To guide initial dosing and identify patients at risk for accumulation.
Timing: Prior to initiation of therapy.
Liver function tests (ALT, AST, bilirubin)
Rationale: Although hepatic metabolism is minor, baseline assessment is prudent, especially in patients with pre-existing liver disease.
Timing: Prior to initiation of therapy.
Routine Monitoring
Symptom relief (e.g., heartburn, abdominal pain)
Frequency: Periodically, as clinically indicated.
Target: Resolution or significant improvement of symptoms.
Action Threshold: Lack of symptom improvement or worsening symptoms may indicate need for dose adjustment, alternative therapy, or further diagnostic workup.
Renal function (CrCl)
Frequency: Periodically, especially in elderly patients or those with pre-existing renal impairment.
Target: Stable CrCl.
Action Threshold: Significant decline in CrCl may necessitate dose reduction.
INR (if on warfarin)
Frequency: More frequently (e.g., daily to weekly) upon initiation or discontinuation of cimetidine, then as per standard warfarin monitoring.
Target: Therapeutic INR range for indication.
Action Threshold: INR outside target range; requires warfarin dose adjustment.
Drug levels (e.g., phenytoin, theophylline, procainamide, lidocaine)
Frequency: Upon initiation or discontinuation of cimetidine, then as clinically indicated.
Target: Therapeutic range for specific drug.
Action Threshold: Levels outside therapeutic range; requires dose adjustment of co-administered drug.
Symptom Monitoring
- Changes in mental status (confusion, disorientation, hallucinations, especially in elderly or renally impaired patients)
- Headache
- Dizziness
- Diarrhea or constipation
- Muscle aches
- Skin rash
- Gynecomastia (with long-term, high-dose use)
- Impotence (with long-term, high-dose use)
- Signs of bleeding (black, tarry stools; coffee-ground vomit; unusual bruising)
- Signs of liver injury (yellowing of skin/eyes, dark urine, persistent nausea/vomiting)
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 should be used during pregnancy only if clearly needed and the potential benefits outweigh the potential risks.
Trimester-Specific Risks:
First Trimester:
No evidence of increased risk of congenital anomalies.
Second Trimester:
No specific risks identified.
Third Trimester:
No specific risks identified.
Lactation
Cimetidine is excreted into breast milk. The American Academy of Pediatrics considers cimetidine to be compatible with breastfeeding. However, monitor the infant for potential side effects such as CNS effects (irritability, drowsiness) or gastrointestinal disturbances (diarrhea). Use with caution, especially in preterm or neonates.
Infant Risk:
Low to Moderate (L3 - Moderately safe; monitor infant for potential side effects).
Pediatric Use
Use with caution. Dosing is weight-based and should be carefully calculated. Neonates and infants may have reduced clearance, increasing risk of adverse effects. CNS effects (e.g., confusion, agitation) may be more pronounced in younger children.
Geriatric Use
Elderly patients are more susceptible to CNS adverse effects (e.g., confusion, disorientation, hallucinations) due to age-related decline in renal function and potential for higher plasma concentrations. Start with lower doses and monitor renal function closely. Dose adjustment is often necessary based on creatinine clearance.
Clinical Information
Clinical Pearls
- Cimetidine is a potent inhibitor of several CYP450 enzymes (especially CYP1A2, 2C9, 2D6), leading to numerous significant drug interactions. Always review concomitant medications.
- Compared to newer H2RAs (like famotidine) and PPIs, cimetidine has a higher potential for drug interactions and CNS side effects.
- Long-term, high-dose use of cimetidine has been associated with gynecomastia and impotence in men, likely due to its antiandrogenic effects.
- Can cause vitamin B12 malabsorption with prolonged use, similar to other acid-suppressing agents.
- While available OTC, patients should be advised to consult a healthcare professional for persistent or severe symptoms to rule out more serious conditions.
Alternative Therapies
- Other H2-receptor antagonists (e.g., Famotidine, Ranitidine (if available), Nizatidine)
- Proton Pump Inhibitors (PPIs) (e.g., Omeprazole, Lansoprazole, Pantoprazole, Esomeprazole, Rabeprazole)
- Antacids (e.g., Calcium carbonate, Aluminum hydroxide/Magnesium hydroxide)
- Sucralfate (for ulcer treatment)
- Prokinetics (e.g., Metoclopramide, for GERD with motility issues)
Cost & Coverage
Average Cost:
Not available (highly variable) per 300mg/5ml oral liquid
Generic Available:
Yes
Insurance Coverage:
Generally covered by most insurance plans, typically as a Tier 1 or Tier 2 generic medication.
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 your 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 taken, the amount, and the time it happened.