Anitid75 mg/5 ml

Anitid is a histamine H2-receptor antagonist historically indicated for the following conditions, where it remains available in a given country/market:

• Established/approved uses: short-term treatment of active duodenal ulcer; maintenance therapy for duodenal ulcer at reduced dosage; treatment of active benign gastric ulcer; treatment of gastroesophageal reflux disease (GERD); treatment and maintenance of healing of erosive esophagitis; treatment of pathological hypersecretory conditions such as Zollinger-Ellison syndrome.
• Symptomatic/OTC-type use: relief of heartburn and acid indigestion (in low-dose formulations, where such formulations remain marketed).

Important regulatory note: Anitid-containing products were withdrawn from the market in several countries (including a market withdrawal requested by the US FDA in April 2020) after testing found that levels of a probable human carcinogen, N-nitrosodimethylamine (NDMA), could increase in the product over time and with storage, including under normal conditions. Continued availability of Anitid therefore depends on the current regulatory status in the local market; patients should confirm with a physician or pharmacist whether Anitid is currently authorized and, where alternatives (such as other H2-blockers or proton pump inhibitors) are recommended instead.

Each formulation of Ranitidine contains ranitidine (as ranitidine hydrochloride) as the active ingredient. Ranitidine has been formulated as tablets, syrup, and injectable solutions in various strengths (commonly 150 mg and 300 mg oral doses, and 25 mg/mL injection), depending on local product availability. Exact strength, dosage form, and inactive ingredients vary by manufacturer and market; consult the specific product label for the formulation actually dispensed.

Anitid is a competitive, reversible histamine H2-receptor antagonist that reduces gastric acid secretion. It was widely used for acid-related upper gastrointestinal disorders, including peptic ulcer disease, GERD, and heartburn. Following the 2019-2020 discovery that some Anitid products could contain unacceptable levels of the probable carcinogen NDMA (N-nitrosodimethylamine), which may increase during storage or with time, national regulators in numerous countries — including the US FDA and Bangladesh's Directorate General of Drug Administration (DGDA) — required withdrawal or suspended marketing of Anitid products. As a result, the availability, marketing status, and recommended use of Anitid now vary substantially by country, and this regulatory history should be disclosed to patients rather than presenting Anitid as a routinely and universally available option.

Anitid belongs to the therapeutic class of Histamine H2-receptor antagonists (H2-blockers), a group of medicines used to reduce stomach acid production.

Ranitidine competitively and reversibly blocks histamine H2-receptors on gastric parietal cells, which reduces both the volume and the acid/hydrogen ion concentration of gastric secretions stimulated by histamine, gastrin, food, and vagal activity. This lowers basal and nocturnal gastric acid secretion, promoting healing of acid-related mucosal injury (such as duodenal and gastric ulcers and erosive esophagitis) and relieving symptoms of GERD and heartburn. Ranitidine has minimal effect on gastric emptying, pancreatic secretion, or lower esophageal sphincter pressure. It has substantially less affinity for the hepatic cytochrome P450 enzyme system than cimetidine, an older H2-blocker, resulting in fewer drug-metabolism interactions, though clinically significant interactions with a few agents are still recognized (see Interactions).

Anitid tablets and syrup may be taken with or without food. Injectable Anitid is administered by a healthcare professional via intramuscular injection or slow intravenous injection/infusion, with the rate and dilution determined by the treating clinician. Do not alter the dose, frequency, or duration without medical advice.

Anitid has a lower potential for drug interactions than older H2-blockers such as cimetidine, but the following clinically significant interactions are recognized:

• Warfarin: Anitid may alter the anticoagulant effect of warfarin; more frequent monitoring of prothrombin time/INR is advised when starting or stopping Anitid in patients on warfarin.
• Procainamide: Anitid reduces renal clearance of procainamide, which can raise procainamide plasma concentrations; monitor for toxicity with concurrent use.
• Drugs dependent on gastric pH for absorption (e.g. certain azole antifungals such as ketoconazole, and some antiretroviral protease inhibitors): the reduced gastric acidity caused by Anitid can reduce absorption of these agents; separate dosing times or alternative therapy may be needed.
• Antacids: high-dose antacids may reduce absorption of oral Anitid; if concurrent use is needed, an interval between doses is advisable.

Anitid is generally well tolerated where it remains available. Reported side effects include:

• Common: headache (sometimes severe), constipation, diarrhea, nausea, abdominal discomfort, dizziness.
• Uncommon/rare: reversible confusion, agitation, depression, or hallucinations (predominantly reported in elderly or severely ill patients and those with renal impairment); malaise; blurred vision; rash; and rare blood count abnormalities (e.g. thrombocytopenia, leukopenia), liver enzyme elevations or hepatitis, bradycardia, and hypersensitivity reactions including anaphylaxis and angioedema.

Patients should seek prompt medical attention for signs of hypersensitivity, unusual bruising/bleeding, jaundice, or persistent confusion.

Anitid has historically been regarded as a relatively low-risk H2-blocker in pregnancy when clinically indicated, but as with all medicines, Anitid should be used in pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; a physician should be consulted before use. Anitid is excreted into breast milk; it should be used with caution during breastfeeding, and only under medical advice, weighing benefit against potential effects on the nursing infant. Given the additional regulatory history of Anitid (see Description), pregnant and breastfeeding individuals should specifically confirm current local availability and physician recommendation before use.

Before starting Anitid, discuss the following with a physician:

• Regulatory/safety history: Anitid products were withdrawn from several markets, including a 2020 US FDA-requested market withdrawal, after detection of the probable carcinogen NDMA, which can increase in the product over time and with storage. Patients should confirm current local regulatory status and use only product that is currently authorized; do not use expired or improperly stored Anitid.
• Masking of malignancy: symptomatic response to Anitid does not exclude the presence of gastric malignancy; in adults with new-onset dyspepsia, especially over age 50 or with alarm features (weight loss, bleeding, anemia, dysphagia), malignancy should be excluded before starting Anitid.
• Renal/hepatic impairment: dosage adjustment is required in significant renal impairment (see Dosage and Administration); use with caution in hepatic impairment.
• Elderly and renally impaired patients: are at higher risk of CNS effects (confusion, agitation, hallucinations) with Anitid; monitor closely.
• Acute porphyria: Anitid has rarely been associated with precipitating acute porphyric attacks; avoid in patients with a history of acute porphyria.
• Duration of use: if symptoms persist despite treatment with Anitid, or worsen, discontinue and consult a physician promptly rather than continuing self-treatment.

Overdose of Anitid is generally associated with an extension of known adverse effects (e.g. gait disturbance, hypotension, and CNS effects) rather than specific new toxicity, but any suspected overdose should be treated as a medical emergency. If overdose of Anitid is suspected, seek immediate medical attention or contact a poison control center/emergency services right away. Management is supportive and symptomatic; gastric decontamination and monitoring of vital signs may be undertaken by medical staff as clinically indicated. Do not attempt home treatment of a suspected Anitid overdose.

Store Anitid at room temperature (below 30°C), protected from light and moisture. Keep out of reach of children. Do not use Anitid beyond its expiry date, as degradation products (including NDMA) may increase with prolonged or improper storage.

Elderly: use Anitid with caution; increased risk of confusion and other CNS effects, particularly with coexisting renal impairment.

Renal impairment: dose reduction of Anitid is required (see Dosage and Administration); accumulation can occur without adjustment.

Hepatic impairment: use Anitid with caution; clinical monitoring is advised.

Pediatric patients: Anitid has established pediatric dosing for ages 1 month to 16 years for ulcer disease and GERD/esophagitis (see Dosage and Administration); safety and efficacy in neonates below 1 month have not been established.

Pregnancy and lactation: see Pregnancy and Lactation section.

Duration of Anitid treatment depends on indication: typically 4-8 weeks for active duodenal or gastric ulcer healing, up to 8 weeks for erosive esophagitis, and as needed (at the lowest effective dose) for GERD/heartburn symptom control, unless a physician directs longer maintenance therapy. Self-treatment with Anitid for heartburn should not exceed the labeled short-term duration (commonly up to 2 weeks) without consulting a physician if symptoms persist.

Ranitidine is classified as a Histamine H2-receptor antagonist (H2-blocker), within the broader category of anti-secretory/anti-ulcer agents.

Ranitidine acts by competitively and reversibly binding to histamine H2-receptors on gastric parietal cells, blocking histamine-stimulated gastric acid secretion and thereby reducing both the volume and acidity of gastric juice. See Pharmacology for full detail.

Category B

Anitid is approved for use in pediatric patients aged 1 month to 16 years for the treatment of duodenal and gastric ulcer disease and for GERD/erosive esophagitis, using weight-based dosing (see Dosage and Administration). Safety and efficacy of Anitid in neonates (under 1 month of age) have not been established, and use in this age group should only occur under specialist medical supervision if considered essential.