We've got mail:A reader from Wexford has been taking a contraceptive pill called Noriday for some time now and has been happily paying €4.11 for a one-month supply.

However, when she went to get her prescription last week, she noticed that the price had risen to €8.39, more than double its previous price.

"Even the girl behind the counter thought there must be some mistake, and she double-checked, first on the computer and then with the pharmacist," she writes. It turns out that the new price was correct.

"I was told that the drug had 'come off control', whatever that means," she says. "An increase of over 100 per cent overnight seems excessive. Do you know if this is a usual occurrence?"

It certainly does seem excessive and we thought that such a price increase was most unusual until later the same day, when another e-mail reached PriceWatch.

A reader has been taking one 300mg capsule of Epanutin, a drug used to treat epilepsy, every day for the past couple of years.

"Until this month, a monthly supply cost €7.80," he writes. "The day before yesterday, I went to the chemist to get another month's supply, and it was €15.14. How can they justify doubling the price?"

So, n the week that prescription drugs are due to fall by 20 per cent, we have two different drugs doubling in price.

Both drugs are manufactured by Pfizer and the company agreed a price increase with the Department of Health that came into effect on February 1st.

We contacted Pfizer and a spokeswoman told us the drugs were off-patent medications which the company was manufacturing and selling at a loss for some years.

She said that until February of this year, Pfizer was charging pharmacists just 70 cent for each packet of 28 Noriday tablets, sold in your local chemist for €4.11.

She said that this price was "unsustainable", so the company applied for the increase.

"The new price we are charging pharmacists is €3.14 which just about covers the cost," the spokeswoman said and pointed out that it was still at the mid-price point for the contraceptive pill in Ireland.

She added that its wholesale price for Epanutin had climbed from €2.80 to €6.95 for the same reason and said that it was still amongst the cheapest of the drugs used to treat epilepsy.

The spokeswoman added that these two drugs were the only two Pfizer-manufactured drugs that have increased in price.

"We would not have been granted the price increases unless we could prove beyond any doubt that it was no longer cost-efficient for us to make then at the existing price".

She also said that she completely understood the shock that our reader experienced and said that the company "welcomed the opportunity to explain it to people".

Another reader contacted us last week after being horrified at the high price of prescription medications in Ireland when compared to prices in Spain.

On holiday in the Canaries recently, our reader from Rathdrum and her husband priced a 28-day supply of a heart medication called Cardura XL at just under €30.

The same drug in this country, however, costs €68.75.

Another drug, called Atonel, which is used to treat osteoporosis, is selling in Irish pharmacies for almost €60, but sells on the Spanish island for closer to €30.

Book early to pay more Joe Darcy sent us in a cautionary tale about the perils of being organised. He recently spent €148 on two tickets through the Aer Lingus website, only to discover that exactly the same tickets were selling two weeks later at a cost of €60.

"I have been told on the phone that it is basically tough luck and I cannot avail of the new price. So much for book early," he says.

• We've Got Mail E-mail: pricewatch@irish-times.ie Text: 085-1645267