Only 10% of people with tension-type headaches experience benefit from taking oral paracetamol, according to a Cochrane review.
Tension-type headache affects about one person in five worldwide. People with frequent, or acute episodic, tension-type headache have between two and 14 headaches every month.
“There may only be a small benefit from a single dose of paracetamol”
Researchers from the UK assessed the usefulness and safety of a single dose of paracetamol for the treatment of frequent tension-type headaches in adults.
The Cochrane review, published this week, includes 23 studies with 8,079 participants who were 18 years or older with frequent tension-type headache, and with moderate or severe pain at the start of treatment.
About 6,000 participants were involved in comparisons between paracetamol 1,000mg and placebo.
The International Headache Society recommends the outcome of being pain-free two hours after taking a medicine as a standard measurement.
The outcome of being pain-free or having only mild pain at two hours was reported by 59 in 100 people taking paracetamol 1,000mg, and in 49 out of 100 people taking placebo. As a result, only 10% of people benefited because of paracetamol 1,000mg.
Meanwhile, about 10% taking paracetamol 1,000mg also reported having a side effect, which was the same as with placebo. Most side effects were mild or moderate in intensity.
Andrew Moore, one of the authors of the Cochrane Review, said: “There may only be a small benefit from a single dose of paracetamol 1,000 mg to those with frequent tension-type headaches.
He added: “Of course, paracetamol is not harmless when taken in large doses or over long periods of time. These results are important for two reasons.
“One is that they form part of a series of reviews into frequent tension-type headaches, hopefully to identify more efficient treatments,” he said. “The other is to improve the way clinical trials are done in future to provide more relevant information about treating this common and often disabling condition.”