Top cough and cold remedies: what works?

MOST of New Zealand’s topselling cough and cold remedies do little to relieve the misery brought on by common respiratory viruses, a pharmacologist says.

You may be just as well off buying no-frills paracetamol and a basic antihistamine, he says.

Stuff.co.nz had 10 of the most popular products sold in supermarkets and pharmacies assessed by clinical pharmacologist and Associate Professor Matthew Doogue, from the University of Otago, Christchurch.

Based on trials of active ingredients found in products, he gave only four – those containing paracetamol, decongestants and antihistamines – the thumbs up.

They were: Otrivin adult spray, Lemsip Max Good Night, Coldrex Cold and Flu Plus capsules, and the pharmacy-only Codral PE Day and Night tablets.

‘‘Those four have ingredients which, in trials, have been shown to improve symptoms; reduce pain, reduce nasal congestionmeasured by nasal air flow and things like that.’’

Others did not rate so well, but manufacturers dispute his views.

Foodstuffs New Zealand said the most popular supplements were those targeted at immunity and containing vitamin C and echinacea.

Yet Doogue said trials on vitamin C and echinacea showed neither relieved cold symptoms when compared to a placebo.

Lozenges such as Strepsils Soothing Honey and Lemon contained mild antiseptics, but there was little evidence they reduced symptoms, he said.

Bonningtons Irish Moss Cough Syrup included menthol, camphor, liquorice extract and carrageenan extract, which had no proven effect on cold symptoms.

Sticking your head over a steaming tub of hot water could be just as effective as Vicks VapoRub, as the product had not been adequately studied, he said.

Doogue said the best cough suppressant was heroin, but no legal substance had been proven to work. Struck down with a cold, he would buy homebrand paracetamol and, if necessary, an antihistamine-only product such as Sudafed.

He did not rule out the placebo effect for some products. ‘‘Everyone has their own favourite – and that’s all good and fine as long as you know why you’re taking it.’’

The maker of Vicks VapoRub, Procter & Gamble said ‘‘numerous published clinical trials have shown that Vicks VapoRub provides relief from nasal congestion and cough’’.

Citations for three of those studies were provided to stuff .co.nz. Doogue remained unmoved, saying that in his view the company’s response ‘‘doesn’t provide sufficient evidence of efficacy to recommend clinical use’’.

Vitaco Health (NZ) defended its Healtheries supplements. ‘‘Garlic, olive leaf, vitamin C, echinacea and zinc are all known to be beneficial in supporting immunity and helping with the symptoms of colds and flu.’’

A list of studies were cited, including one which ‘‘concluded that echinacea products slightly reduce the risk of getting a cold in healthy individuals (preventative action)’’, one that confirmed ‘‘it may be beneficial for common cold patients to try vitamin C’’, and one that found zinc ‘‘may reduce the severity and duration of the common cold’’.

Doogue thought the studies could be classed as ‘‘pseudo science’’ because in his opinion the outcomes were ‘‘fairly weak’’ and they did not provide a body of respected evidence to support their use.

Berocca, a winter best-seller according to Foodstuffs, should not have been included in the list as it was not marketed as a cough and cold remedy, Bayer New Zealand spokesman William Malpass said.

‘‘Berocca is a multivitamin, not a cough and cold product.’’

Doogue said the bar for a drug’s performance needed to be high. ‘‘A body of evidence underpinned by controlled clinical studies is needed before something can be recommended for clinical use.’’ Virologist Dr Lance Jennings said his cold-remedy pack would contain paracetamol, lozenges and Kleenex anti-viral tissues – which he helped develop in the 1980s.

The tissues contained ascorbic acid and ‘‘a tiny bit of detergent’’, which effectively killed viruses.

He supported the use of large amounts of vitamin C to reduce symptoms of a cold, such as a runny nose. A study he did at the University of Wisconsin in the 1980s showed symptoms were lessened for Rhinovirus 16.

While most cough and cold products had little science behind them, infections and the effectiveness of treatments varied from person to person, Jennings said.

‘‘We’re all individuals and our immune systems vary, responses to infections vary – so that’s a possible explanation.’’

Other popular remedies such as honey and garlic were unproven, though Jennings said Russians had effectively worn garlic around the neck to keep people away and reduce transmission of the virus.

He said a seasonal vaccine was the best way to beat influenza.

The common cold is likely to plague most adults two to four times a year and children six to 12 times a year.