Controlled Drugs - a UK list

Guidance

List of most commonly encountered drugs currently controlled under the misuse of drugs legislation

Updated 1 April 2025

https://www.gov.uk/government/publications/controlled-drugs-list--2/list-of-most-commonly-encountered-drugs-currently-controlled-under-the-misuse-of-drugs-legislation

 

No details here as the list can and does change. Therefore anything quoted could be out of date.

Last updated 22/06/2025 

What saline can I use for injections?

Some people buy products, such as vitamin B12 in a powder form, which require to be dissolved in a liquid so they can be injected.

Hence the question as to what liquid that should be! 

• It must be sterile. 
• It must be saline (sodium chloride in water).
• It should be an isotonic 0.9% saline solution.
• It should be a non-pyrogenic saline for injection which is clearly identified as such.

Non-pyrogenic means: Non-fever inducing!

If you boiled water in a kettle, that water might well be sterile.

But the remains of any bacteria, fungal spores, etc., which will usually be present in the water, albeit in tiny amounts, can cause issues when injected. Even if the water was entirely safe for drinking before being boiled.

There are many sterile saline sources which are not non-pyrogenic and would be unsuitable for injection purposes. These include saline for nebulisers, for eye drops, or containing a preservative, or a lower concentration saline used for some infusions

Any individual product might or might not be OK but, unless officially non-pyrogenic, you simply cannot know it will be safe.

In other words, always get Saline for Injection that is appropriately labelled. In the UK, it would probably say:

Sodium Chloride 0.9% w/v Solution for Injection

In German, it would probably say: Injektionslösung

Though it might also have other wording like company and brand names, etc. 

Least fillers/excipients?

A common request is know which product (typically levothyroxine, but could be almost any medicine) has the least fillers?

I find this very difficult to answer for several reasons.

Excipients is a word which covers all ingredients in a medicine except for the active pharmaceutical ingredients. Yes, some of these might be present as fillers (bulking agents), but they have many other functions like disintegrants, glidants, colourants, coatings, etc. That is why I prefer to use the term excipients.

But another issue is what is meant by "least"? The smallest number of individual excipients? Or the smallest quantity of excipients in total?

A couple of non-pharmaceutical examples to illustrate:

Ferrero Rocher has about 17 ingredients.

Milk Chocolate 30% (

Sugar, 
Cocoa Butter, 
Cocoa Mass, 
Skimmed Milk Powder, 
Concentrated Butter, 
Emulsifier: Lecithins (Soya), 
Vanillin), 

Hazelnuts (28.5%), 
Sugar, 
Palm Oil, 
Wheat Flour, 
Whey Powder (Milk), 
Fat-Reduced Cocoa, 
Emulsifier: Lecithins (Soya), 
Raising Agent (Sodium Bicarbonate), 
Salt, 
Vanillin.

Total weight of one: 12.5 grams

A loaf of bread has four ingredients.

Wholewheat flour,
Water,
Salt,
Yeast

Total weight of one: 800 grams 

The loaf weighs the same as 64 Ferrero Rocher sweets. But has a mere four ingredients. About a quarter the number.

And it is likely that there is more than 12.5 grams - the total weight of a Ferrero Rocher - of each and every ingredient in the loaf.

You might complain "Of course a loaf is much bigger than a Ferrero Rocher!". I fully accept that. But tablets also vary quite substantially, if not as extreme as these illustrations.

Trouble is, when comparing you might be much happier with four ingredients that are familiar, than 17 of which several are not things we are likely to have in our kitchens.

On the other hand, there will be less than a fraction of a gram of several of the Ferrero Rocher ingredients. Quite possibly little enough to cope with even if you could not take larger amounts.

For thyroid hormones, we often have to take more than one tablet to reach our required dose. Quite common to need 100 + 50 + 25. You must add all the individual tablets you need. Also, a higher dose tablet might well be the same size as a 25 microgram tablet or, in some cases, smaller, which makes this more awkward to calculate.

Proportions of levothyroxine in tablets and oral solutions

A typical levothyroxine tablet might weigh 100 milligrams and contain 100 micrograms of the actual levothyroxine ingredient.

That is, the tablet contains 1000 parts of excipients to one part of levothyroxine. 

Obviously that needs scaling on the basis of tablet weight and dosage. 

A typical levothyroxine oral solution (liquid) might weigh 5 grams (5000 milligrams), and contain 100 micrograms of levothyroxine ingredient.

That is, the oral solution contains 50,000 parts of excipients to one part of levothyroxine.  

Think through what you really want to achieve.

Thus we have the oral solutions which are sometimes described as having "no excipients" actually containing fifty times the amount of excipients as do tablets.

Summary

My own view is that we need to identify excipients we know we need to avoid and exclude products that contain them. Then look through what options remain. You might be disappointed that there are only one or two.

Availability is also an issue. We often do not have the choice of all the products that could be available. 

Last updated 20/06/2025. 

 

 

 

 

Vitamin C and Levothyroxine

Discussion

A widely discussed issue is whether Vitamin C enhances absorption of levothyroxine. For example, these two papers:

The interplay between vitamin C and thyroid.

https://europepmc.org/article/MED/37246589

https://doi.org/10.1002/edm2.432

Levothyroxine treatment and gastric juice pH in humans: the proof of concept. 

https://europepmc.org/article/MED/35477833

https://doi.org/10.1007/s12020-022-03056-1

If you decide to try this approach, there are some important points.

Form of Vitamin C 

There are several forms of Vitamin C. But the forms which are not ascorbic acid will not help.

That is, sodium ascorbate and calcium ascorbate are unlikely to have any positive effect.

Other Ingredients

And many forms of Vitamin C are not just the active ingredient but other substances like those in the list below. Some are very pure ascorbic acid but some have numerous other ingredients. And each of those ingredients needs to be considered.

• microcrystalline cellulose
• magnesium stearate
• polyethylene glycol
• sodium starch glycolate
• silica colloidal anhydrous
• talc
• syrup (sucrose)
• potato starch
• hypromellose (derived from cellulose) capsule
• calcium laurate

 

https://helvella.blogspot.com/2025/06/vitamin-c-and-levothyroxine.html