Common cold - Treatments

Decongestants

If you've got a blocked nose, medicines called decongestants can help for a short time. Decongestants help reduce the swelling inside your nose so you can breathe more easily. But the benefit is only small. Decongestants come as tablets or as sprays and drops you put up your nose.

You can buy many different decongestant nasal sprays and drops at chemists. Some examples (with their brand names) are:

• ephedrine
• oxymetazoline (Sudafed, Vicks Sinex)
• xylometazoline (Non Drowsy Sudafed).

Or you can take decongestant pills containing pseudoephedrine (Sudafed) or phenylephrine (Sudafed PE).

Decongestants are also often used together with a painkiller or an antihistamine (see section below on antihistamines) in the cold medicines you can buy in a pharmacy. There are lots available. You can take them as pills, powders, capsules or a syrup. Here are a few examples. The decongestant pseudophedrine is combined with three different antihistamines:

• Paracetamol and pseudoephedrine (Non-Drowsy Sinutab)
• Paracetamol and phenylephrine (Lemsip)
• Pseudoephedrine and triprolidine (Sudafed Plus, Multi-action Actifed Syrup).

We found one summary of the research (a systematic review) that looked at decongestants.[3] The summary showed that a single dose of a decongestant can help relieve a blocked nose for three hours to ten hours. But the benefit is likely to be quite small. You'll get the same small benefit if you continue to use a decongestant for three to five days. But we don't know if decongestants work in children because there hasn't been any research.

The studies we looked at found that side effects were no more common among people who used a decongestant than among those who used a dummy treatment (placebo).[3] But we know that some decongestant sprays can sometimes irritate the lining of your nose, give you headaches and make you feel sick.[4]

Pseudophedrine can make your heart race, make you feel restless and make it hard to sleep.

You shouldn't use decongestant nasal sprays for longer than a week. After that, they can cause rebound congestion. This means you get a blocked nose again after you stop taking them.[5] This is more likely to happen with sprays and drops containing oxymetazoline and xylometazoline than ephedrine.

You shouldn't use decongestants if you're taking a medicine called a monoamine oxidase inhibitor. These drugs are usually used to treat depression. You could get dangerously high blood pressure if you take the two together.[5]

You should also be careful about taking decongestant tablets if you've got another medical condition, such as a heart problem, high blood pressure or diabetes. Talk to your doctor if you're not certain which medicines you can take.

Paracetamol is an ingredient in lots of cold remedies. You must take care to avoid accidentally taking too much. A paracetamol overdose can be life-threatening.

Antihistamines

Antihistamines are usually used to treat allergies such as hay fever. If you take an antihistamine when you've got a cold, your nose may be slightly less runny and you may sneeze less. But the benefit is only small. And your overall cold symptoms probably won't improve.

The antihistamines used in cold remedies include chlorphenamine and diphenhydramine. Lots of different medicines are available. The brands sold as cold remedies often contain a painkiller (such as paracetamol or ibuprofen) and a decongestant (such as phenylephrine or pseudophedrine) as well as an antihistamine. You can buy them as pills, capsules, powders or a syrup. A few examples of the cold remedies you can buy in a pharmacy are:

• Dextromethorphan, paracetamol and promethazine (Night Nurse)
• Paracetamol and promethazine (Medised).

Because paracetamol is an ingredient in lots of cold remedies, you must take care to avoid accidentally taking too much. A paracetamol overdose can be life-threatening. You need to read the labels of all the medicines you're taking, to ensure that you're not taking more paracetamol than the recommended dose. You might find it simpler to avoid taking one of these remedies with any other medicine containing paracetamol.

One summary of the research (a systematic review) showed that taking antihistamines made no difference to the symptoms of a cold on the whole.[6] And they don't seem to help with a cough.[7] Another summary found that antihistamines only helped a little bit with the sneezing or runny nose you get with a cold.[8]

Antihistamines can have side effects. They include:[6]

• Dizziness
• A dry mouth
• A headache
• Drowsiness.

Doctors don't usually recommend you take an antihistamine alone to help your cold symptoms. But antihistamines are often used together with painkillers and decongestants in the cold remedies you take at night. Some antihistamines make you drowsy. So if your cold disturbs your sleep, a treatment containing an antihistamine may help at bed time.[9]

You shouldn't give antihistamines to children under 2. To find out more, see Treating coughs and colds in children.

Echinacea

Echinacea is a herbal remedy made from a plant. It's been used for many years to treat lots of illnesses. You can buy it as tablets from health food shops. You can also get it as tea.

Some studies have shown that echinacea helps with cold symptoms, but others studies found that it doesn't help at all. We looked at a summary of the research (a systematic review):[10]

• Some of the studies in the summary found that echinacea worked better than a dummy treatment (a placebo). People who took echinacea at the start of a cold had a less runny nose. They also got better more quickly.
• Other studies found that echinacea didn't help.
• Most of the studies were of poor quality. So we can't rely on their results.

There are more than 200 different echinacea products available. They're all made in different ways. Some are made from the roots, and others are made from the leaves or the whole plant. And they may contain different amounts of the plant. So it can be hard to know exactly what you're buying.

Some people take echinacea to try to prevent colds. We haven't looked at the research on this, so we don't know whether it works.

Herbal treatments can cause side effects. In one study we found, 7 percent of children who took echinacea had a rash.[11] Some people had a serious allergic reaction (known as anaphylaxis) after taking echinacea.[12]

In the studies included in the summary, about 1 in 10 people who took echinacea had mild side effects. But so did people taking a dummy treatment (a placebo), so we don't know that echinacea caused the problems.[10] The side effects included:

• Nausea
• Heartburn
• Constipation
• Itching or burning
• Numbness
• A headache
• A dry mouth.

Breathing in water vapour

If you've got a cold your nose can get blocked from swelling and mucus. People often try breathing in (inhaling) water vapour to clear their nose. You can try bending your head over a bowl of hot water, with a towel covering your head.

We don't know for certain if breathing in water vapour can make your nose less blocked and help reduce the soreness from a cold. There hasn't been enough research to say.

We found a summary (a systematic review) of the research that looked at people who tried inhaling water vapour.[13] It looked at six studies:

• Some of the research showed that breathing in water vapour helped symptoms immediately or a few days later.
• But one study found no improvement with this treatment.
• The studies were all of poor quality. So we can't be sure whether this treatment helps.

The research didn't show that breathing in water vapour could be harmful. But there may be a danger of spilling hot water.

Zinc

Zinc is a mineral. You mainly get it from food. Red meat contains a lot of zinc. People have tried taking extra zinc to treat a cold. You can buy lots of different mineral supplements that contain zinc.

The research on people taking zinc for a cold looked at zinc lozenges or a zinc gel that people put inside their noses. But there's not much evidence that taking zinc lozenges or putting a zinc gel inside your nose can help you recover quicker from a cold.

We found three summaries (systematic reviews) of the research that compared zinc lozenges with a dummy treatment (a placebo):[14] [15] [16]

• Most of the research showed that taking zinc is unlikely to help your cold.
• But one of the summaries found people who took zinc lozenges were more likely to be better after a week than people who took a placebo.[14]
• One small study found that colds were a few days shorter after treatment with zinc.[16]

We also found some studies of people who put a zinc gel inside their nose to treat cold symptoms:

• Two studies showed that colds didn't last as long for people who took zinc.[17] [18]
• One study found the zinc gel didn't help.[19]

People taking zinc lozenges were more likely to have mouth irritation, an unpleasant taste, feel sick or get diarrhoea.[14] About 2 in 5 people who used the zinc gel in their nose got a tingling or burning feeling.[17]

Vitamin C

Your body needs some vitamin C to work properly. You get this vitamin from fruits and vegetables such as oranges, grapefruits and broccoli. You can also buy vitamin tablets that contain vitamin C. Some people think that taking extra vitamin C might help with a cold.

But there's good research to show that taking high doses of vitamin C is unlikely to help you recover from a cold.

A summary of the research (a systematic review) found that colds lasted just as long for people who took up to 4 grams (0.14 ounces) a day of vitamin C.[20] People who took vitamin C had symptoms that were just as severe as people who took a dummy treatment (a placebo).

The research didn't mention any side effects of taking vitamin C for a cold.[20] In studies of people taking vitamin C every day to prevent colds, no one had any serious problems.

Some people take vitamin C to try to prevent colds. We haven't looked at the research on this, so we don't know whether or not it works.

Antibiotics

Antibiotics are drugs that kill germs called bacteria. Because colds are usually caused by viruses, antibiotics probably won't help. And antibiotics can cause side effects, especially diarrhoea.

We looked at two summaries (systematic reviews) of the research.[21] [22] They both found that antibiotics don't cure colds or improve people's symptoms.

Antibiotics can be harmful. An upset stomach is a common side effect from taking antibiotics.

Also, if antibiotics are used too much, bacteria start to become resistant to them. This means antibiotics can no longer kill some kinds of bacteria. So doctors are careful only to give antibiotics to people who really need them. And antibiotics are not usually recommended for colds, because people get better without them.

But some people with a cold go on to get another condition, such as an ear infection or sinusitis. If this happens, you might need antibiotics.

Cough medicine

You can buy lots of different cough medicines in a pharmacy:

• Some cough medicines are meant to stop you coughing. These often contain the drug dextromethorphan.
• Other cough medicines aim to help you cough up mucus. These often contain a chemical called guaifenesin.
• Syrupy cough medicines may help soothe your throat if you have an irritating dry cough.[23] One example is simple linctus.

We don't know how well these treatments work. Some doctors think most of the benefit comes from the placebo effect (this means you feel better because you're expecting to feel better after taking a medicine).[24]

A large review looked at all the research on over-the-counter cough medicines.[7] Overall, the researchers said there was no good evidence to prove that cough medicines work, or that they don't. But some people find cough medicines help them feel better, or help them get a good night's sleep.

You shouldn't use many cough medicines in children under 2. To learn more, see Treating coughs and colds in children.

You should not take medication containing dextromethorpan if you have an underlying problem, such as chronic bronchitis.[25] Ask your doctor if you're not certain if a treatment is safe for you to take.

Menthol

Menthol is a chemical with a strong smell. It's found in peppermint oil, but can also be man-made. Some people breathe it in to try to clear their blocked nose. It sometimes comes combined with other strong-smelling chemicals such as eucalyptus oil.

There are many ways you can take menthol. Some common brands are Karvol and Vicks Vaporub. You can get:

• Capsules of menthol that you break open and drop onto a tissue
• Powders that you dissolve in water
• Pads with menthol in them
• Plastic sticks that you put up your nose.

For children with a blocked nose, you can rub menthol on their pyjamas or pillow at night, but this isn't recommended for children under 3 months.[26]