Shutterstock Cimetidine - Chemical Structure
More specifically, it is the progenitor of the class of histamine H2 receptor antagonists. The other anti-H2 active ingredients still used today in therapy were then developed starting from cimetidine: famotidine, nizatidine and ranitidine.
While until some time ago cimetidine was used in the treatment of ulcers (duodenal, gastric, relapsing), gastroesophageal reflux esophagitis and Zollinger-Ellison syndrome (medicines that require a medical prescription to be dispensed), currently (February 2020) this active ingredient is mostly used in the symptomatic treatment of excessive stomach acid secretion and the burning that typically derives from it (over-the-counter or OTC drugs).
Note: on the market it is still possible to find some cimetidine-based drugs indicated to combat ulcers, Zollinger-Ellison syndrome and reflux esophagitis; but these are products that will remain on the market only while stocks last (last update in January 2020).
Cimetidine for Veterinary Use
Cimetidine is also used in a veterinary medicine (Zitac Vet®) which is used in the symptomatic treatment for the reduction of vomiting associated with chronic gastritis in dogs. Of course, in order to be dispensed, this medicine requires the presentation of a specific medical prescription. veterinary (single copy repeatable recipe) Like any other veterinary drug, the price is fully paid by the citizen.
Examples of Medicines containing Cimetidine currently used in therapy
- Cimetidina Farmakopea®
- Etideme®
- Ulis® (out of stock)
or duodenal;
Remember that cimetidine can mask the symptoms of still undetected stomach cancer, thus slowing down the diagnosis of the disease; this is the reason why it is necessary to consult your doctor before taking cimetidine if the symptoms have appeared recently, new ones appear and / or those already present are modified, even more so if you are in mature or advanced age .
It is also important to tell your doctor if you are intolerant to some sugars, as they may be present as excipients in cimetidine medicines.
Please Note
- Cimetidine may cause dizziness or sleepiness by interfering with the ability to drive and use machines. Therefore, caution is recommended.
- If your symptoms do not improve or worsen after 7 days of treatment with cimetidine, you should seek immediate medical attention.
In particular, the administration of cimetidine and the following drugs should be avoided or otherwise require cautious evaluation and close surveillance by the physician:
- Antiarrhythmic drugs, such as, for example, amiodarone, quinidine, propafenone, lidocaine, procainamide;
- Anticoagulant drugs such as warfarin and acenocoumarol;
- Antiepileptic drugs such as phenytoin, valproate and carbamazepine;
- Cyclosporine;
- Theophylline.
The use of cimetidine in combination with the following drugs involves fewer risks but still requires careful medical surveillance:
- Opioid analgesics;
- Anthelmintic drugs;
- Antibiotics;
- Antidepressant drugs;
- Medicines to treat diabetes (for example, metformin and sulfonylureas);
- Antifungal drugs;
- Antihistamines for the treatment of allergies;
- Antimalarial drugs;
- Antipsychotics;
- Antivirals;
- Anxiolytics and sedative hypnotic drugs;
- Beta-blocking drugs;
- Calcium channel blockers;
- Cytotoxic anticancer drugs to treat cancer (for example, fluorouracil);
- Hormonal antagonists such as octreotide;
- Anti-migraine drugs such as triptans
- Sildenafil.
Finally, remember that cimetidine should not be administered with antacid drugs containing aluminum or magnesium as these could interfere with its absorption, thus decreasing its effectiveness.
, manifesting undesirable effects different in type and intensity, or not manifesting them at all.
Among the side effects observed during treatment with cimetidine, we mention:
- Diarrhea and other gastrointestinal disorders;
- Headache;
- Dizziness;
- Tiredness;
- Skin rashes, alopecia;
- Alteration of liver values;
- Bradycardia;
- Atrioventricular block.
More rarely, the following have also been observed:
- Allergic and hypersensitivity reactions;
- Confusion, hallucinations, depression;
- Acute pancreatitis;
- Interstitial nephritis;
- Tachycardia;
- Agranulocytosis, pancytopenia, thrombocytopenia.
Finally, it should be noted that cases of gynecomastia and impotence have also been reported. In any case, by respecting the instructions given on the package leaflet of the cimetidine-based medicine to be taken, the risk of the appearance of side effects is reduced.
Cimetidine overdose
Symptoms such as:
- Dilated pupils
- Difficulty of speaking;
- Agitation;
- Severe neurological symptoms.
The treatment consists in the implementation of maneuvers useful for the removal of the drug from the gastrointestinal tract, in the monitoring of the patient and in the initiation of the necessary supportive therapies.
In case of cimetidine overdose - whether it is known or suspected - it is therefore advisable to contact your doctor immediately and go to the nearest emergency room, taking care to take the package of the medicine taken with you.
. We remember, in fact, that the activation of the H2 receptors localized on the mucosa of the stomach by histamine stimulates the secretion of gastric acids.and is excreted in breast milk, its use in pregnant women and breastfeeding mothers is generally contraindicated.
There are no adequate and well-controlled clinical studies on the use of the active ingredient in pregnant women and it is true that pre-clinical toxicity studies have not revealed possible negative effects on the fetus, but despite this, a risk for this cannot be excluded. "last in case of use of the active principle by the pregnant woman. Therefore, the doctor may decide to administer the drug to a pregnant woman only if he considers it absolutely necessary and indispensable and only after a "careful evaluation of the relationship between the potential risks for the fetus and the expected benefits for the mother.
As for breastfeeding, however, cimetidine can cause harm to the infant; therefore, if treatment with the active ingredient in question is indispensable, breastfeeding should be interrupted.
In any case, pregnant women and nursing mothers should NOT take cimetidine without the prior consultation of their doctor and / or gynecologist.