Mercury pharma confirmed today (31.05.2013) that their liothyronine tablets are already back in stock. Pharmacies can order Mercury liothyronine tables from either of 2 wholesalers: AAH and Alliance Healthcare. All pharmacies have an account with Alliance Healthcare (a proportion also use AAH). As a result, your pharmacy should be able to obtain Mercury liothyronine tablets very soon, if they haven't already.
Just to clarify a few points which have been raised...
1. The shortage of liothyronine in the UK was not caused by exporting, or quotas. Given that the UK version of liothyronine is unusually expensive, foreign pharmaceutical wholesalers would not wish to purchase UK stock. Exporting occurs only when UK branded medicines are substantially less expensive than the same brand in other EU countries. The current wholesale price of Mercury liothyronine tablets is high (net price, £52.46 per pack of 28). As far as I know, the shortage was caused by a delay in obtaining the active ingredient, resulting in a delay in tablet production.
2. Mercury pharma are able to charge a high price for their liothyronine tablets because no other manufacturer currently sells this drug in the UK; there is therefore no price competition to keep the price low. Bear in mind, however, that Mercury are not preventing other companies from launching their own liothyronine (this product is not patent protected). The Department of Health are not able to force any other manufacturers to obtain a license and start producing this product. As a result, other competing manufacturers may or may not start to sell liothyronine in the UK over the coming years. This is not something that the NHS can control.
Because liothyronine is naturally present in the body (and blood), it is difficult for companies to demonstrate that their tablets are equivalent to the reference brand (which is performed by measuring blood levels after a tablet has been taken). This may be the reason for the absence of other suppliers. Another reason could be difficulties in sourcing the active ingredient.
3. There is no reason to think that Mercury would deliberately create a shortage of liothyronine, as was suggested above, this would simply reduce sales. Due to the fact that they are the UK's sole supplier, they *already* have control over the price (which they have increased dramatically over the last few years).
4. Mercury pharma have an unusually large number of out-of-stock situations. This is by no means unique to liothyronine - far from it. I have seldom known a company to have so many out-of-stocks. It is therefore rather unfortunate in my opinion that the sole supplier of this important medicine happens to be Mercury!
5. Unlicensed liothyronine products imported from the EU are licensed products in the country where they are normally sold. There is no reason to doubt the quality of these imports, they are regulated medicines in the country of origin, it's just that they are not regulated by the UK authorities. They will contain exactly the dose of liothyronine specified on the label eg. 20mcg. The issue is that there are other ingredients in the tablets apart from the active drug. These ingredients may be slightly different between Mercury liothyronine and the European versions. This could result in a very slight difference in the amount of liothyronine which is actually absorbed from the tablet (ie. the bioavailability may be different). This is only a potential problem. I do not think it is likely to be a problem in the majority of patients. Fortunately, few patients will now need to use the imports, unless the UK product becomes unavailable once again, which is quite possible.
I hope that this information is useful.