Antihistamines, h2-antagonists

Author:Prof. Dr. med. Peter Altmeyer

Last updated on: 13.09.2021

Synonym(s)

H2 antagonists; H2-receptor blockers

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DefinitionThis section has been translated automatically.

Drugs that block H2-receptors of the document cells in the stomach and lead to the healing of ventricular and duodenal ulcers by reducing acid secretion.

IndicationThis section has been translated automatically.

H2-antagonists are used in dermatology as concomitant medication in systemic glucocorticoid, immunosuppressive or cytostatic therapy.

Limited indicationThis section has been translated automatically.

Pregnancy, nursing, renal failure.

Dosage and method of useThis section has been translated automatically.

S. Tab.

Undesirable effectsThis section has been translated automatically.

Allergic reactions, CNS disorders, dizziness, blood formation disorders, eosinophilia, bronchospasms, gastrointestinal disorders.

InteractionsThis section has been translated automatically.

S. Tab.

ContraindicationThis section has been translated automatically.

Paragroup allergy (applies only to suspensions), sorbitol intolerance (applies only to suspensions), children and adolescents < 16 years, porphyria, severe hepatic dysfunction, anuria .

TablesThis section has been translated automatically.

Major interactions of H2 antagonists

Acenocoumarol	Bleeding tendency ↑
Barbiturates	Barbiturate levels ↑
Captopril	Neuropathy ↑
Carbamazepine	Carbamazepine levels ↑
Carmustine	Carmustine toxicity ↑, myelosuppression ↑
Chlordiazepoxide	Chlordiazepoxide levels ↑
Chlorpromazine	Fatigue ↑
Clomethiazole	Clomethiazole levels ↑
Digitoxin	Digitoxin toxicity ↑
Diltiazem	Diltiazem toxicity ↑
Iron	Iron level ↓
Erythromycin	Erythromycin toxicity ↑, hearing impairment ↑.
Halofrantine	Halofrantine bioavailability ↓, avoid combination.
Hydromorphone	Hydromorphone levels ↑
Isradipine	Isradipine levels ↑, RR drop, halve dose of isradipine
Itraconazole	Itraconazole levels ↓, take 2 hrs apart.
Ketoconazole	Ketoconazole level ↓
Labetalol	Labetalol level ↑
Levomethadone	Levomethadone level ↑
Lidocaine i.v.	Lidocaine level ↑, halve lidocaine dose.
Magnesium antacids	H2 antagonist levels ↓, take 2 hrs apart.
Mebendazole	Mebendazole levels ↑
Metformin	Metformin levels↑, lactic acidosis
Metoclopramide	H2 antagonist levels ↓, take 2 hrs apart.
Metoprolol	Metoprolol levels ↑, bradycardia
Nifedipine	Nifedipine level ↑, RR drop.
Nicotine abuse	H2 antagonist effect ↓
Opioid analgesics	Opioid toxicity ↑, seizures, confusional states, respiratory failure
Phenytoin	Phenytoin levels ↑.
Procainamide	Procainamide levels ↑, conduction disorders
Propanolol	Propanolol levels ↑, bradycardia
Rifabutin	Rifabutin levels ↑.
Sulfonylurea antidiabetics	Antidiabetic effect ↑
Terbinafine	Terbinafine levels ↑
Tetracyclines	Tetracycline effect ↓
Theophylline	Theophylline levels ↑
Valproic acid	Valproic acid level ↑
Warfarin	Bleeding tendency ↑
Zidovudine	Zidovudine toxicity ↑

Overview of the main H2 antagonists and their dosage.

Active ingredient	Dosage	Preparation
Cimetidine	400 mg/day p.o.	Tagamet
Famotidine	20 mg/day p.o. in the evening	Pepdul
Nizatadine	200 mg/day p.o. in the evening	Nizax
Ranitidine	300 mg/day p.o. in the evening	Sostril, Zantic

Authors

Last updated on: 13.09.2021

Author: Prof. Dr. med. Peter Altmeyer