Antiacidi
Revisione paritaria di Dr Doug McKechnie, MRCGPUltimo aggiornamento di Dr Surangi Mendis, MRCGPUltimo aggiornamento 10 Ago 2023
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In questa serie:Indigestion medicineInibitori della pompa protonicaBloccanti H2
Gli antiacidi neutralizzano l'acido prodotto dallo stomaco. Sono comunemente usati per l'indigestione e il reflusso acido che causano bruciore di stomaco. La maggior parte delle persone che assumono antiacidi non sviluppa effetti collaterali.
A colpo d'occhio
Antacids are medicines that help neutralise stomach acid.
They are used to relieve symptoms of acid reflux, heartburn, and indigestion.
Antacids include aluminium hydroxide, magnesium carbonate, and magnesium trisilicate.
They are available to buy from pharmacies or on prescription, as tablets or liquids.
Common side-effects can include diarrhoea, constipation, and burping.
Seek medical advice if symptoms worsen, or if you experience vomiting blood or unintentional weight loss.

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What are antacids?
Antacids are a group (class) of medicines which help to neutralise the acid content of your stomach.
Some antacids are combined with another medicine called simeticone which helps to reduce wind (flatulence).
Another group of medicines called alginates are found in some brands of antacid medication. Alginates are added to help protect the lining of the gullet (oesophagus) from stomach acid.
Alginates include sodium alginate and alginic acid. They are present in antacid medications.
Types of antacids
Torna ai contenutiAntacids include:
Magnesium carbonate.
These come in various brand names and are available as tablets and liquids.
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What conditions are antacids used to treat?
Torna ai contenutiAntacids may be used:
To reduce the symptoms of acid reflux which may cause heartburn or inflammation of the gullet (oesophagitis). These conditions are sometimes called gastro-oesophageal reflux disease (GORD).
To relieve some of the symptoms caused by ulcers in the stomach e part of the gut called the duodenum.
In other conditions where it is helpful to neutralise stomach acid. For example, for occasional bouts of indigestion (dyspepsia).
Before the discovery of other more modern medicines, antacids were commonly used for the above conditions. They were also used to help heal ulcers in the stomach and duodenum.
Medicines called inibitori della pompa protonica (IPP) e H2-receptor antagonists (commonly called H2 blockers) are now more widely used for these conditions. They are much more effective than antacids. Unlike antacids, which simply neutralise the acid for a short period, these modern medicines work by reducing the amount of acid made by the stomach.
Nota: some studies have questioned whether long-term use of PPIs may be linked to cancro allo stomaco. More studies are needed. Therefore, current advice is that PPIs should be taken at the lowest dose, for the shortest length of time possible.
Some people may be able to take them occasionally rather than on a daily basis. However, if you find that other medicines don't help and you have persistent symptoms, the advice is to carry on taking PPI medication for as long as necessary.
However, antacids still have a place. They are most commonly used to provide quick relief of symptoms caused by stomach acid - in particular, in people who have occasional bouts of mild dyspepsia or heartburn.
How do antacids work?
Torna ai contenutiUpper gastrointestinal tract and acid

Your stomach normally produces acid to help with the digestion of food and to kill germs (bacteria). This acid is corrosive so your body produces a natural mucous barrier which protects the lining of the stomach from being worn away (eroded).
In some people this barrier may have broken down and this allows the acid to damage the stomach, causing an ulcer. In others there may be a problem with the muscular band at the top of the stomach (the sphincter) that keeps the stomach tightly closed, allowing the acid to escape and irritate the gullet (oesophagus). This is called acid reflux, which can cause heartburn and/or inflammation of the gullet (oesophagitis).
Antacids work by counteracting (neutralising) the acid in your stomach. They do this because the chemicals in antacids are bases (alkalis) which are the opposite of acids. A reaction between an acid and base is called neutralisation. This neutralisation makes the stomach contents less corrosive. This can help to relieve the pain associated with ulcers and the burning sensation in acid reflux.
When antacids work on stomach acid, they can produce gas which may cause wind (flatulence). Simeticone helps to stop this foaming effect and may sometimes be included within antacid medications.
Many of the common antacids also include alginates. Most alginates work by forming a gel which floats on top of the stomach contents. The gel acts as a protective barrier, preventing stomach acid from irritating the oesophagus.
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Antacid side-effects
Torna ai contenutiMost people who take an antacid do not have any side-effects. However, side-effects occur in a small number of users.
The most common are:
Burping.
Magnesium-containing antacids tend to be lassativo whereas aluminium-containing antacids tend to be constipating. Antacids containing both magnesium and aluminium may balance out these effects and so minimise any possible side-effects of diarrhoea or constipation.
For a full list of all the side-effects and possible interactions associated with your medicine, consult the leaflet that comes with your medication.
If you are taking antacids, you should avoid taking them at the same time as you take other medication. This is because antacids can affect how well other medication is absorbed.
Can I buy antacids or do I need a prescription?
Torna ai contenutiYou can buy most brands of antacids at pharmacies, or you may obtain them on prescription.
When is the best time to take antacids?
Torna ai contenutiAntacids are often taken to relieve symptoms or when symptoms are expected. Your doctor or pharmacist will advise you of the dose needed and how often you should take it. Read the leaflet that comes with your particular brand for further information.
How quickly do antacids work?
Torna ai contenutiGenerally antacids provide quick relief for problems such as heartburn caused by reflux. However, the relief of symptoms may only be short-lived.
How long is treatment needed for?
Torna ai contenutiYour doctor may prescribe an antacid to have on standby so that you only take it to relieve your symptoms when they occur, rather than every day. Read the leaflet that comes with your particular brand for further information.
Who can and cannot take antacids?
Torna ai contenutiA full list of people who should not take antacids is included with the information leaflet that comes in the medicine packet. If you are prescribed or buy an antacid, read this to be sure you are safe to take it.
Altre considerazioni
Torna ai contenutiYou should talk to your doctor if your symptoms worsen, or if you experience any of the following problems which can indicate a serious gut disorder:
Bringing up (vomiting) blood. This may be obviously fresh blood but altered blood in vomit can look like dark brown or black ground coffee. This is called coffee-ground vomit.
Blood in your stools (faeces). This may be obvious blood, or it may make your stools black.
Perdita di peso non intenzionale.
Difficulty swallowing, including food getting stuck in the gullet (oesophagus).
Persistent tummy (abdominal) pain.
Persistent vomiting.
Scelte del paziente per Digestive health medicines

Trattamenti e farmaci
Inibitori della pompa protonica
Gli inibitori della pompa protonica riducono la quantità di acido prodotta dallo stomaco. Sono comunemente usati per trattare il reflusso acido e le ulcere dello stomaco e di una parte dell'intestino chiamata duodeno. La maggior parte delle persone che assumono un inibitore della pompa protonica non sviluppa effetti collaterali.
di Dr Philippa Vincent, MRCGP

Trattamenti e farmaci
Bloccanti H2
I bloccanti H2 riducono la quantità di acido prodotta dallo stomaco. Vengono usati in condizioni in cui è utile ridurre l'acidità dello stomaco. Ad esempio, per aiutare con il reflusso acido che provoca bruciore di stomaco. La maggior parte delle persone che assumono i bloccanti H2 non sviluppa effetti collaterali.
di Dr Doug McKechnie, MRCGP

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Domande frequenti
If I am already taking other medications, can I still use antacids?
If you are taking other medicines, you should avoid taking antacids at the same time. This is because antacids can affect how well your other medications are absorbed by the body. It's important to consult the leaflet that comes with your antacid for a full list of possible interactions.
What is the difference between antacids, PPIs, and H2 blockers?
Antacids work by neutralising the existing acid in your stomach for a short period, providing quick relief for symptoms. In contrast, Proton Pump Inhibitors (PPIs) and H2-receptor antagonists (H2 blockers) are more modern medicines that work by reducing the amount of acid your stomach produces, making them more effective for ongoing conditions.
How do alginates help when they are included in antacid medications?
Alginates, such as sodium alginate and alginic acid, are often added to antacid medications. Most alginates work by forming a protective gel that floats on top of your stomach contents. This gel acts as a barrier, preventing stomach acid from irritating the lining of your gullet (oesophagus), which can help with symptoms like heartburn and oesophagitis.
What should I do if I experience side-effects from antacids?
Most people don't experience side-effects from antacids, but some common ones include diarrhoea, constipation, and burping. Magnesium-containing antacids can cause diarrhoea, while aluminium-containing ones can cause constipation. Combinations of both may balance these effects. If you think you've had a side-effect, you can report it on the Yellow Card Scheme, an online system for reporting suspected side-effects from medicines.
Can antacids cure stomach ulcers?
Antacids can help relieve symptoms associated with stomach and duodenal ulcers by neutralising stomach acid. However, before modern medicines like proton pump inhibitors (PPIs) were developed, antacids were used to help heal ulcers. Nowadays, PPIs and H2-receptor antagonists are more commonly used and are more effective for these conditions.
Why do some antacids also contain simeticone?
Antacids can sometimes produce gas when they neutralise stomach acid, which may lead to wind (flatulence). Simeticone is a medicine often combined with antacids to help reduce this effect by preventing the foaming that can occur in the stomach.
When should I see a doctor if I'm taking antacids for stomach problems?
You should talk to your doctor if your symptoms worsen, or if you experience any serious problems such as vomiting blood (which can look like dark brown or black ground coffee), blood in your stools (which may be obvious or make them black), unintentional weight loss, difficulty swallowing, persistent tummy pain, or persistent vomiting. These could indicate a more serious gut disorder.
Ulteriori letture e riferimenti
- Malattia da reflusso gastroesofageo e dispepsia negli adulti: indagine e gestione; Linee guida cliniche NICE (settembre 2014 - ultimo aggiornamento ottobre 2019)
- Dispepsia - GERD comprovata; NICE CKS, luglio 2023 (accesso solo Regno Unito)
- Dispepsia - funzionale comprovata; NICE CKS, dicembre 2022 (accesso solo Regno Unito)
- Dyspepsia - pregnancy-associated; NICE CKS, giugno 2024 (accesso solo nel Regno Unito)
- Milivojevic V, Rankovic I, Krstic MN, et al; Sfida della dispepsia in gastroenterologia di medicina generale. Dig Dis. 2022;40(3):270-275. doi: 10.1159/000517668. Epub 2021 Jun 14.
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Informazioni sull'autoreVisualizza il profilo completo

Dr Surangi Mendis, MRCGP
Consulente e Autore Medico
MBBS, BSc (1st), MRCGP (2014), DFSRH, PGcert otology and audiology
Surangi Mendis è una consulente in Medicina Audiovestibolare e Neuro-otologia presso il Royal National ENT e Eastman Dental Hospitals, UCLH.
Informazioni sul recensoreVisualizza il profilo completo

Dr Doug McKechnie, MRCGP
Scrittore Medico
MA, MBBS, MSc, DRCOG, MRCP(UK), MRCGP(2021), FHEA
Il dottor Doug McKechnie è un medico di base del NHS che lavora a Londra. Lavora a tempo pieno in ambito clinico ed è anche Vice Responsabile del modulo di Pratica Clinica e Professionale presso la Scuola di Medicina dell'University College London.
Storia dell'articolo
Le informazioni su questa pagina sono scritte e revisionate da clinici qualificati.
Prossima revisione prevista: 8 ago 2028
10 Ago 2023 | Ultima versione

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