Body weight, age, other medical conditions, and drugs the patient is already taking are factors that affect ranitidine dosage. This drug reduces the amount of acid produced by the stomach, and is used to treat gastric and duodenal ulcers, as well as esophageal erosions. Certain health problems preclude the use of ranitidine, and smokers should beware of the increased effect of nicotine.
When something disrupts the protective mucous lining of the stomach, acid can eat away at the organ and cause a gastric ulcer. The sore may also form in the duodenum, where it is known as a duodenal ulcer. Acid reflux disease or a hiatal hernia can cause the acid to back up into the esophagus and create erosions, which place the patient at a higher risk for esophageal cancer. Ranitidine is one of several common acid blocking drugs that reduce the amount of acide the stomach secretes and allows lesions to heal.
The usual adult ranitidine dosage is 300 mg once a day or 150 mg twice a day if the larger dose makes the patient nauseous. Dosage for children from one to 16 years old ranges from 2-10 mg daily. The drug has not been established for use during pregnancy, so women should tell their doctors if they are pregnant or plan to become pregnant while on ranitidine therapy. It should only be used if the benefit is stronger than the risks. The ranitidine dosage may be adjusted as needed.
An intravenous ranitidine dosage should be used with caution in patients who have a predisposition to cardiac disturbances. Bradycardia has been reported in cases where the drug was introduced too rapidly. Liver problems can affect the dosage because the drug is metabolized through that organ. Moderate to severe renal dysfunction affects elimination of medicines from the system and calls for a lower ranitidine dosage. Those on dialysis should wait until after their treatment to take ranitidine so the level of the drug in their system is not reduced.
People with porphyria, a genetic disorder that interferes with the body's production of heme, should not take ranitidine. Although it is rare, the drug may initiate an acute attack of the disease. The effervescent form of this medicine contains phenylalanine, which is a substance phenylketonuria (PKU) patients need to avoid because their bodies will not be able to process it.
There are interactions with sucralfate, an ulcer medication, and ketoconazole, an anti-fungal. Ranitidine inhibits the clearance of nicotine by about 30%, so smokers should be cautious when taking it, and will need to watch for signs of nicotine effects. Close monitoring and adjustment of the ranitidine dosage should catch any problems.