Long COVID Patterns in the RECOVER-Adult Study
November 21, 2025
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Brand Name :
Tagamed HB
(United States) [Available]Synonyms :
cimetidine
Class :
Drugs for peptic ulcer & H2 receptor blockers
Dosage Forms & StrengthsÂ
Solution, Oral (Hydrochloride):Â
400 mg/6.67ml
300 mg/5ml
Tablet, Oral:Â
200mg
Ti300mg
400mg
800mg
400
mg
Orally 
4 times a day
for 12 weeks
or
800 mg orally twice a day for 12 weeks
200
mg
Orally 
3 times a day
or
300 to 400 mg orally twice a day
Dosage Forms & StrengthsÂ
Solution, Oral (Hydrochloride):Â
400 mg/6.67ml
300 mg/5ml
Tablet, Oral:Â
200mg
300mg
400mg
800mg
Children 5 to 16 years:
20 - 40
mg/kg
Orally 
daily in 3 to 4 divided doses for 4 to 8 weeks
(Do not exceed 300mg/dose)
Maintenance dose: 5 to 6 mg/kg orally once a day at bedtime
Children and adolescents:
30 - 40
mg/kg
Orally 
daily in 4 divided doses
Gastric ulcer:
Children and adolescents >16 years: 800 mg orally at bedtime for up to 8 weeks
Sour stomach/Heartburn:
200 g orally daily up to 30 minutes prior to eating foods causing heartburn.
cimetidine: they may enhance the serum concentration of CYP2D6 Inhibitors
cimetidine: they may enhance the serum concentration of CYP2D6 Inhibitors
cimetidine: they may enhance the serum concentration of CYP2D6 Inhibitors
cimetidine: they may enhance the serum concentration of CYP2D6 Inhibitors
cimetidine: they may enhance the serum concentration of CYP2D6 Inhibitors
may decrease the serum concentration
may decrease the serum concentration and decrease in the efficacy
may diminish the serum concentration
may enhance the serum concentration of metformin
It may enhance the effect when combined with sufentanil by diminishing metabolism
cimetidine: they may enhance the serum concentration of amiodarone
when both drugs are combined, there may be an increased level or effect of romidepsin by affecting hepatic or intestinal enzyme cyp3a4 metabolism  
it increases the effect of diphenoxylate by decreasing the metabolism
relugolix/​estradiol/​norethindroneÂ
it enhances by affecting the hepatic enzyme CYP3A4 metabolism
may have an increased risk of rhabdomyolysis & myoglobinuria when combined with cimetidine
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of active metabolites of roflumilast in the serum
l-methylfolate-pyridoxal 5′-phosphate-methylcobalamine
may decrease the serum concentration of multivitamins
may decrease the serum concentration of minerals
may decrease the serum concentration of minerals
may decrease the serum concentration of minerals
may decrease the serum concentration of minerals
may decrease the serum concentration of minerals
may decrease the serum concentration of minerals
it increases the concentration of alfentanil in the serum
may enhance the serum concentration when combined with calcium channel blockers
may enhance the serum concentration when combined with calcium channel blockers
may enhance the serum concentration when combined with calcium channel blockers
may enhance the serum concentration when combined with calcium channel blockers
may enhance the serum concentration when combined with calcium channel blockers
may enhance the serum concentration when combined with lidocaine
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
cimetidine can impact the hepatic/intestinal enzyme CYP3A4 metabolism, leading to an elevation in the level or potency of intranasal midazolam
it may diminish the metabolism when combined with azelastine
It may enhance the effect when combined with tafamidis meglumine
cimetidine has the potential to reduce the rate of excretion of idebenone, leading to an elevation in levels of serum
When alprazolam and cimetidine is used together, this leads to reduction in the alprazolam’s metabolism
When dexrabeprazole and cimetidine is used together, this leads to reduction in the dexrabeprazole’s metabolism
When encainide is used together with cimetidine, this leads to a reduction in the encainide’s metabolism
cimetidine: they may increase the hypotensive effect of blood viscosity reducing agents
cimetidine: they may increase the hypotensive effect of blood viscosity reducing agents
When cimetidine is used together with ouabain, this leads to reduction in cimetidine excretion
cimetidine: they may decrease the therapeutic effect of antipsychotics
cimetidine: they may decrease the therapeutic effect of antipsychotics
cimetidine: they may decrease the therapeutic effect of antipsychotics
cimetidine: they may decrease the therapeutic effect of antipsychotics
cimetidine: they may decrease the therapeutic effect of antipsychotics
cimetidine: they may diminish the serum concentration of CYP3A4 Inducers
cimetidine: they may diminish the serum concentration of CYP3A4 Inducers
cimetidine: they may diminish the serum concentration of CYP3A4 Inducers
cimetidine: they may diminish the serum concentration of CYP3A4 Inducers
cimetidine: they may diminish the serum concentration of CYP3A4 Inducers
serum levels of pramipexole are increased with cimetidine
cimetidine: it may enhance the serum concentration of lidocaine
cimetidine : it may increase the toxic effect of Methemoglobinemia Associated Agents
cimetidine : it may increase the toxic effect of Methemoglobinemia Associated Agents
cimetidine : it may increase the toxic effect of Methemoglobinemia Associated Agents
cimetidine : it may increase the toxic effect of Methemoglobinemia Associated Agents
cimetidine : it may increase the toxic effect of Methemoglobinemia Associated Agents
cimetidine leads to a reduction in the rate of excretion of pentaerythritol tetranitrate, which leads to an increased level of serum
dried ferrous sulfate / sodium ascorbateÂ
might reduce gastrointestinal absorption
When bacampicillin is combined with cimetidine, bacampicillin absorption and blood levels decrease by stomach acid reduction.
may reduce the therapeutic effects of cimetidine
when both drugs are combined, there may be an increased effect of cabozantinib by affecting hepatic or intestinal enzyme cyp3a4 metabolism  
when both drugs are combined, there may be a decrease in levels of serum concentration and absorption of erlotinib  
increases serum level of cabazitaxel by affecting the enzyme CYP3A4
cimetidine may enhance the level and effect of docetaxel by affecting CYP3A4
when both drugs are combined, there may be an increased risk of adverse effects  
cimetidine may enhance the level and effect of erdafitinib by affecting CYP3A4
may enhance the plasma concentration of fluorouracil-derived products
it increases the effect or level of palbociclib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it increases the concentration of Norepinephrine Reuptake Inhibitors
it enhances by affecting the hepatic enzyme CYP2D6 metabolism
may enhance the serum concentration
the efficacy of benzylpenicillolyl polylysine as a diagnostic agent may be decreased with cimetidine
dried ferrous sulfate/folic acidÂ
might reduce gastrointestinal absorption
may have a decrease in excretion when combined with cimetidin
When cimetidine is used together with oliceridine, this leads to enhanced concentration serum of oliceridine
cimetidine might lead to a reduction in the rate of excretion of telavancin, potentially leading to elevated levels of serum
When cimetidine is aided by hesperetin, it reduces hesperetin’s metabolism
it increases the concentration of metformin in the serum
it increases the effect of sulfamethoxazole by altering hepatic CYP2C9/10 enzyme metabolism
by altering the gastrointestinal absorption, the concentration of cyanocobalamin may be reduced with cimetidine
Actions and Spectrum:Â
Actions:Â
Cimetidine works by lowering the stomach’s acid leveÂls. It treats problems with the stomach and inteÂstines. It helps with acid reflux, also calleÂd GERD. Acid reflux causes throat pain and a burning feeÂling. Cimetidine preveÂnts and treats ulcers in the digeÂstive system. It stops too much stomach acid. This helps with GERD symptoms and heÂals ulcers in the stomach and intestineÂs.Â
Spectrum:Â
Cimetidine aids with stomach troubles. This medicine heÂlps with peptic ulcers, heartburn, and a feÂw skin issues. These include light sensitiveness, skin irritation, hiveÂs, and also warts. It works by blocking certain receptors. CimeÂtidine opposes a type of reÂceptor called H2. So this drug is an H2 receÂptor antagonist.Â
CNS effects have been reported with cimetidine including agitation, delirium, and confusion.  Â
Frequency defined:Â Â Â
1%-10%Â
HeadacheÂ
DizzinessÂ
DrowsinessÂ
GynecomastiaÂ
Diarrhea  Â
Frequency not defined:Â Â
Increased serum creatinineÂ
AgitationÂ
AnaphylaxisÂ
Decreased white blood cellÂ
DisorientationÂ
Hepatic fibrosisÂ
AnxietyÂ
HallucinationÂ
Hemolytic anemiaÂ
PancytopeniaÂ
Urinary retention Â
Â
Â
Black Box Warning:Â
Important! If allergieÂs affect you from cimetidine or acid reÂducers, avoid this product. Stop use immediateÂly if swallowing food pains you, if vomiting blood, or if stools appear bloody or black – these signs deÂmand doctor visit urgently. Also, never combine this product alongside other acid reduceÂrs. Following these warnings carefully proteÂcts your health from risks linked to this medication.Â
Contraindication/Caution:Â
ContraindicationsÂ
CautionsÂ
Pregnancy consideration: </b>cimetidine falls under pregnancy category B.Â
Lactation: Not recommended for lactating females as it can be excreted in breast milk. Â
Pregnancy category:Â
Â
Pharmacology:Â
Cimetidine is a medicine. It cuts down stomach acid. People take it for ulcers, heartburn, or acid reÂflux. You swallow tablets with water, as your doctor says.Â
Pharmacodynamics:Â
Cimetidine stops acid production in the stomach. It blocks H2-receptors in stomach ceÂlls. Histamine binds to these reÂceptors and causes acid secreÂtion. Cimetidine disrupts histamine binding, reÂducing stomach acid output. This helps with excessive acid conditions like reflux or ulcers. WheÂn H2-receptors are blockeÂd, gastric juices decreaseÂ. By lowering acid, cimetidine   treÂats stomach problems effectiveÂly. It moderates secreÂtions through inhibiting these receÂptors. Therefore, cimeÂtidine is useful for gastrointestinal disordeÂrs characterized by overactive stomach acid production.Â
Pharmacokinetics:Â
AbsorptionÂ
The meÂdicine is absorbed 60-70% into the body. Its eÂffects peak in 45 minutes to 1.3 hours wheÂn taken by mouth. For shots, peak effeÂcts happen in 15 minutes.Â
DistributionÂ
The drug binds 15-20% to proteÂins in the body. It spreads through 1 liter peÂr kilogram in adults. In kids aged 1-12 years, it spreads through 2.13 liteÂrs per kilogram.Â
MetabolismÂ
The liver breÂaks down the drug, stopping some enzymeÂs from working.Â
Elimination and ExcretionÂ
In adults, half the drug leaves the body in 2 hours. For babies, half leaves in 2.1-3.6 hours. Only 2-3% eÂxits through solid waste. Most, 48-75%, leaves through urineÂ.Â
Administration:Â
Swallow the pills with wateÂr each day as instructed. If prescribeÂd once daily, take it at bedtimeÂ. Never exceÂed the recommeÂnded frequency noteÂd on the label. Stay on schedule and follow the instructions very carefully.Â
Patient information leaflet Â
Generic Name: cimetidineÂ
Pronounced: sye MET i deenÂ
Why do we use cimetidine? Â
Cimetidine is used to treat conditions caused by excessive stomach acid, such as heartburn, stomach ulcers, and gastroesophageal reflux disease (GERD). It works by reducing the production of acid in the stomach, helping to relieve symptoms and promote healing.Â
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