When heartburn hits, it's tempting to pop a pill. A growing body of research, however, suggests that the drugs favoured now to relieve acidity come with worrying side effects. A new antacid may make the adverse effects a thing of the past. A group of researchers in a Calcutta lab has already tested it successfully on animals; human trials will start in a city public hospital soon.

Antacid medication is basically of three types - proton-pump inhibitors or PPIs (omeprazole, rabeprazole, pantoprazole, esomeprazole and the like), histamine2 (H2) receptor blockers (ranitidine, famotidine, cimetidine, nizatidine) and the earlier generation chewable, liquid or effervescent antacids, which contain aluminium hydroxide, magnesium hydroxide [commonly known as milk of magnesia] or sodium bicarbonate [baking soda].

Research has shown that PPIs have numerous side effects, from deadly infections in the stomach and impaired vitamin absorption, to an increased risk of kidney disease, heart attack and even dementia. While H2 blocker drugs are known to spark off headaches, constipation and nausea, their long-term use has not been studied as extensively as that of PPIs. Old-fashioned antacids have milder effects like constipation, diarrhoea or, in worst cases, acid rebound.

"The new drug molecule we have designed is on the lines of these drugs, but more effective and with minimal side effects," says Jui Chakraborty, a senior scientist at the Central Glass & Ceramic Research Institute (CGCRI) at Jadavpur, a lab under the umbrella of the Council of Scientific and Industrial Research (CSIR). "It is a potent, inorganic, ceramic-based antacid, providing instant relief," she added.

The stomach produces hydrochloric acid of industrial strength, similar to that used to remove rust from steel. The acid plays a key role in the digestion of proteins, by activating digestive enzymes in the stomach. "The acid also kills harmful bacteria ingested with contaminated food," says Dr Goutam Das, head, department of gastroenterology at AMRI Hospitals. To ensure that the fluid in the stomach does not become too acidic, the stomach produces a bicarbonate (a base) as buffer. "The right level of acid [measured on the pH scale] needs to be maintained in the stomach for proper digestion," he adds.

A faulty or irregular diet, physical and mental stress as well as lack of sleep can cause over-production of acid in the stomach. Spicy and greasy foods can also increase acid production, as can excessive consumption of fibre, which takes longer to digest, leading to greater acid production.

This excess acid can lead to an upset stomach, bloating or other intestinal problems. "Many people experience acid reflux when some of the acidic contents of the stomach go back up into the oesophagus creating a burning pain (heartburn) in the lower chest area after meals," says Dr Das of AMRI. The corrosive action of excess acid may also burn the stomach, causing peptic ulcers.

Chalk (calcium carbonate) has been chewed for centuries to counter acidity. Ancient physicians also prescribed different inorganic ceramic compounds such as calcium carbonates or milk of magnesia. The older proprietary antacids - the effervescent sodium bicarbonates (or baking soda, a grandmother's remedy for tummy aches) and aluminium hydroxides - neutralise excess stomach acid after it's secreted. The new drug acts in much the same way.

"This earlier generation of antacids have a local action, unlike the proton-pump inhibitors and H2 blockers," says Siddhartha Bandyopadhyay, head of bioceramics and coating division at CGCRI. The newer drugs go through the liver to mix in the blood and stop acid secretion. If the patient has high-blood pressure or diabetes and is on medication for them, then PPIs and H2 blockers put extra pressure on the liver.

In addition, since these newer drugs stop the pump producing acid in the stomach, there is an increased risk of bacterial infections that can cause intractable diarrhoea. That is why nowadays most gastroenterologists prescribe PPIs at the lowest effective dose possible and for the shortest length of time. "And you do not really need these drugs if you need just a temporary suspension of acid production - say for those who suffer from hyperacidity after dinner," says Dr Das. One of the old-fashioned antacids will suffice.

Despite the adverse effects, PPIs and H2 blockers are immensely popular. "You pop a pill once in the morning and you knock out acid for the day. It's so convenient," says Dr Das. The problem with older antacids is that they are not effective as long. You need to pop a pill every two-three hours to keep excess acid in check.

Although the ceramic-based drug created at CGCRI is on the lines of the older pills, it stays active for over six hours. "Our drug can also be administered at a lower dose," says Chakraborty. Moreover, unlike the fast-acting effervescent fruit salts, the drug doesn't cause the body to retain water or add extra sodium to blood, which is harmful for patients with high blood pressure or cardiac diseases. Says Bandyopadhyay, "Since the drug acts locally in the stomach, it doesn't affect the liver either."

After testing it successfully on laboratory rats, the researchers are gearing up for its human trial. Dr Rupnarayan Bhattacharya, professor and head, department of plastic surgery at R.G. Kar Medical College and Hospital in Calcutta, will help organise the clinical trial. "We are planning to test the drug on patients who undergo acute stress, such as patients with severe burn injury," he says. Burn patients are so traumatised that they have excessive acid secretion in the stomach. That needs to be countered by antacids or acid blockers. Otherwise, they undergo erosion of the stomach and grow ulcers. "The plan is to administer the drug to a group of patients and offer PPIs or acid blockers to equal number of patients," says Dr Bhattacharya. Some patients will get the CGCRI drug and the rest will be given the conventional treatment for three to six months. Then doctors and researchers will measure the impact of the drug. "We are now in the process of filing an Indian patent and obtaining approvals for the human trial," says Chakraborty.

According to K. Muralidharan, director of CGCRI, if clinical trials are successful, the drug can be an effective alternative to antacids of similar category in the market. "We are all waiting with our fingers crossed for the results of the human trial," he says.

ANTACIDS: PROS AND CONS

Drug type: Proton Pump Inhibitors (omeprazole, rabeprazole, pantoprazole, esomeprazole)

Prescribed for: Acid reflux, heartburn, peptic ulcers, gastritis, some forms of stomach tumours

Serious side effects: Heart attack, dementia, kidney disease and bone fractures

Drug type: H2 blockers (ranitidine, famotidine, cimetidine, nizatidine)

Prescribed for: Acid reflux, heartburn, peptic ulcers, gastritis

Serious side effects: Scaling skin, changes in vision, confusion, agitation, wheezing, chest tightness, irregular heartbeat, hallucinations * 

Drug type: Effervescent sodium bicarbonate

Prescribed for: Indigestion, heartburn, upset stomach

Serious side effects: Swelling of feet, muscle pain or twitching, frequent urination, rapid breathing, fluid retention in patients with heart failure, hypertension or kidney problem

Drug type: Aluminium hydroxide and magnesium hydroxide

Prescribed for: Heartburn, acid indigestion, bloating and stomach discomfort

Serious side effects: Severe allergic reactions (rash, itching, swelling of mouth, face, lips), tightness in the chest, slow reflexes, vomitting

*These reactions are rare