A 'new trend' could mean an uneasy Spring for hay fever sufferers.
The Medicine Shortages Index has found there are 247 medicines used by Irish patients currently out of stock.
This is an increase of 19 since the end of last month, and a 38% increase since the index began last October.
The index is prepared by Azure Pharmaceuticals.
CEO Sandra Gannon told Breakfast Briefing a plastic shortage is one of the issues.
"What we are seeing is a trend emerging with medicines that use plastics in their delivery," she said.
"Products like nasal sprays, inhalers and eye drops are now appearing on the Medicines Index for the first time in numbers.
"Obviously coming in to hay fever season, some of these are critical for patients to manage their hay fever.
"That's the new trend that we're seeing".
Another shortage is coming from eye drops.
Ms Gannon explained: "We're seeing antibiotic eye drops, we're seeing eye drops that patients use when they've got dry eye.
"That's a very irritating condition for anyone who experiences it".
She said knock-on effects are continuing to impact some over-the-counter antibiotics.
"As we saw earlier over Christmas, a lot of the over-the-counter meds to treat coughs and colds are out of stock.
"We're still seeing pressure on antibiotics, although it is easing as less patients are requiring them.
"There are still a number of antibiotics that are taken on a spoon, they're out of stock."
Why are there shortages?
Ms Gannon said these shortages are due to a number of reasons.
"It can be quite simply that the demand is higher than predicted, and therefore there just isn't enough stock manufactured - that's the case with some of the cough and cold medicines.
"It can be issues such as back in the manufacturing side, there can be some quality issues that need to be resolved before the product is made available."
She said sometimes it can be price-related for commercial reasons.
"The product is not available at the price that is being paid for it, and therefore manufacturers are not able to supply it".
There are also shortages affecting some medicines for long-term conditions.
"At the minute there are some anti-epileptics and medicines to treat blood pressure out of stock.
"They would be more chronic conditions.
"If they're out of stock, there's a lot of work that has to be done by pharmacists and doctors and consultants in hospital in order to give the patient something that will treat their condition".
'Medicines being withdrawn'
Ms Gannon said this is an EU-wide problem which "is not simply an issue that is going to go away on its own."
"Price is a factor, it's been recognised within... the European Medicines Regulatory Agency," she said.
"It's certainly one factor to ensure that products and medicines are getting to the markets.
"If the price that's being paid is lower than everywhere else and not covering the costs of manufacturing and transportation and all of the energy hikes, then that's going to put markets where the prices are really low under pressure."
She said there needs to be meaningful dialogue between authorities and drug-makers.
"We need to look at this in the short-term and then we need to look at it in the longer-term," she said.
"It's not just shortages, we're talking about medicines being withdrawn from markets.
"These are not expensive medicines, they're all off-patent and very cheap.
"We need to look at what are we willing to pay to maintain these medicines on the market, and ensure that patients have access to them in the longer-term," she added.