Ranitidine HCL

Ranitidine HCL

About your treatment

Your doctor has ordered ranitidine hydrochloride to decrease the acid produced by your stomach.

Ranitidine may be added to an intravenous fluid that will drip through a needle or catheter placed in your vein for 15-20 minutes, one to four times a day. It also may be added to your total parenteral nutrition (TPN) solution.

Ranitidine decreases acid in your stomach to help treat an ulcer or prevent one from developing. Ranitidine helps to decrease the stomach pain, diarrhea, and loss of appetite that ulcers can cause. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of your treatment using laboratory tests and physical examinations. It is important to keep all appointments with your doctor and the laboratory. The length of treatment depends on how you respond to the medication.

Precautions

Before administering ranitidine, tell your doctor and pharmacist if you are allergic to ranitidine or any other drugs. tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially acetaminophen (Tylenol), anticoagulants ('blood thinners') such as warfarin (Coumadin), propantheline, and vitamins. tell your doctor if you have or have ever had kidney or liver disease or acute porphyria. tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking ranitidine, call your doctor.

Administering your medication

Before you administer ranitidine, look at the solution closely. It should be clear and free of floating material. Gently squeeze the bag or observe the solution container to make sure there are no leaks. Do not use the solution if it is discolored, if it contains particles, or if the bag or container leaks. Use a new solution, but show the damaged one to your health care provider.

It is important that you use your medication exactly as directed. Do not change your dosing schedule without talking to your health care provider. Your health care provider may tell you to stop your infusion if you have a mechanical problem (such as a blockage in the tubing, needle, or catheter); if you have to stop an infusion, call your health care provider immediately so your therapy can continue.

Side effects

Although side effects from ranitidine are not common, they can occur. Tell your health care provider if any of these symptoms are severe or do not go away: headache dizziness constipation diarrhea stomach pain upset stomach

Storing your medication

Your health care provider probably will give you a several-day supply of ranitidine at a time. If you are receiving ranitidine intravenously (in your vein), you probably will be told to store it in the refrigerator or freezer. Take your next dose from the refrigerator 1 hour before using it; place it in a clean, dry area to allow it to warm to room temperature. If you are told to store additional ranitidine in the freezer, always move a 24-hour supply to the refrigerator for the next day's use. Do not refreeze medications.

If you are receiving ranitidine mixed with TPN, you may be directed to keep it in a clean, dry area away from heat.

Store your medication only as directed. Make sure you understand what you need to store your medication properly.

Keep your supplies in a clean, dry place when you are not using them, and keep all medications and supplies out of reach of children. Your health care provider will tell you how to throw away used needles, syringes, tubing, and containers to avoid accidental injury.

Ranitidine HCl[tempform.htm]

Chemistry - An H2 receptor antagonist, ranitidine HCl occurs as a white to pale-yellow granular substance with a bitter taste and a sulfur-like odor. The drug has pKas of 8.2 and 2.7. One gram is approximately soluble in 1.5 ml of water or 6 ml of alcohol. The commercially available injection has a pH of 6.7-7.3.

Storage/Stability/Compatibility - Ranitidine tablets should be stored in tight, light-resis­tant containers at room temperature. The injectable product should be stored protected from light and at a temperature less than 30°C. A slight darkening of the injectable solu­tion does not affect the potency of the drug. Ranitidine injection is reportedly stable for up to 48 hours when mixed with the com­monly used IV solutions (including 5% sodium bicarbonate).

Pharmacology - At the H2 receptors of the parietal cells, ranitidine competitively inhibits histamine, thereby reducing gastric acid output both during basal conditions and when stimulated by food, amino acids, pentagastrin, histamine or insulin. Ranitidine is between 3-13 times more potent (on a molar basis) as cimetidine.

Ranitidine can cause gastric emptying times to be delayed, but the clinical significance of this effect is not known. Lower esophageal sphincter pressures may be increased by ranitidine. By decreasing the amount of gastric juice produced, ranitidine also decreases the amount of pepsin secreted. Ranitidine, unlike cimetidine, does not appear to have any appreciable effect on serum prolactin levels, although it may inhibit the release of vasopressin.

Uses/Indications - In veterinary medicine, ranitidine has been used for the treatment and/or prophylaxis of gastric, abomasal and duodenal ulcers, uremic gastritis, stress-re­lated or drug-induced erosive gastritis, esophagitis, duodenal gastric reflux and esophageal reflux. It has also been employed to treat hypersecretory conditions associated with gastri­nomas and systemic mastocytosis.

Pharmacokinetics - Pharmacokinetic data for veterinary species is limited for this prod­uct. In dogs, the oral bioavailability is approximately 81%, serum half-life is 2.2 hours and volume of distribution 2.6 L/kg.

In humans, ranitidine is absorbed rapidly after oral administration, but undergoes exten­sive first-pass metabolism with a net systemic bioavailability of approximately 50%. Peak levels occur at about 2-3 hours after oral dosing. Food does not appreciably alter the extent of absorption or the peak serum levels attained.

Ranitidine is distributed widely throughout the body and is only 10-19% bound to plasma proteins. Ranitidine is distributed into human milk at levels of 25-100% of those found in the plasma.

Ranitidine is both excreted in the urine by the kidneys (via glomerular filtration and tubular secretion) and metabolized in the liver to inactive metabolites; accumulation of the drug can occur in patients with renal insufficiency. The serum half-life of ranitidine in humans averages from 2-3 hours. The duration of action at usual doses is from 8-12 hours.

Contraindications/Precautions - Ranitidine is contraindicated in patients who are hyper­sensitive to it. It should be used cautiously and possibly at reduced dosage in patients with diminished renal function. Ranitidine has caused increased serum ALT levels in humans receiving high, IV doses for longer than 5 days. The manufacturer recommends that in high dose, chronic therapy that serum ALT values be considered for monitoring.

Adverse Effects/Warnings - Adverse effects appear to be very rare in animals at the dosages generally used. Potential adverse effects (documented in humans) that might be seen include mental confusion and headache. Rarely, agranulocytosis may develop and if given rapidly IV, transient cardiac arrhythmias may be seen. Pain at the injection site may be noted after IM administration.

Overdosage - Clinical experience with ranitidine overdosage is limited. In laboratory animals, very high dosages (225 mg/kg/day) have been associated with muscular tremors, vomiting and rapid respirations. Single doses of 1 gram/kg in rodents did not cause death.

Treatment of overdoses in animals should be handled using standard protocols for oral ingestions of drugs; symptoms may be treated symptomatically and supportively if necessary. Hemodialysis and peritoneal dialysis have been noted to remove ranitidine from the body.

Drug Interactions - Unlike cimetidine, ranitidine appears to only have minimal effects on the hepatic metabolism of drugs and is unlikely to cause clinically relevant drug interactions via this mechanism. Propantheline Bromide delays the absorption, but increases the peak serum level of ran­itidine. The relative bioavailability of ranitidine may be increased by 23% when propantheline is administered concomitantly with ranitidine. Antacids may decrease the absorption of ranitidine; give at separate times (2 hours apart) if used concurrently. Ranitidine may decrease the renal clearance of procainamide, but the clinical relevance of this interaction is unclear at this time. The manufacturer states that ranitidine may alter the bioavailability of certain drugs through pH-dependent effects, changes in volume of distribution or an unknown effect. Further information is pending.

Drug/Laboratory Interactions - Ranitidine may cause a false-positive urine protein reading when using Multistix? The sulfosalicylic acid reagent is recommended for deter­mining urine protein when the patient is concomitantly receiving ranitidine.