Which dyes are used?
Coloring agents that are also used as food additives (E-numbers) are usually used for medicines. Which colorants are permitted depends on the legislation of the relevant countries. For Switzerland, the specifications published in the Medicines Approval Ordinance (AMZV), in Pharmacopoea Helvetica and in the Additives Ordinance apply. The following list shows a small selection of permitted dyes:
- Azo dyes (various colors)
- Tartrazine (yellow)
- Quinoline yellow (yellow)
- Yellow orange S (orange)
- Azorubin (red)
- Amaranth (red)
- Ponceau 4R (red)
- Iron oxides (red, yellow, black)
- Erythrosine (red)
- Indigotine (blue)
- Chlorophyll (green)
- Curcumin (yellow-orange)
- Riboflavin (yellow)
- Lycopene (red)
- Titanium dioxide (white)
Why are medications dyed?
Most pharmaceutical active ingredients and excipients are white or colorless. This then also applies to the tablets or solutions made from them. Various reasons exist why colorants are added to medications. One reason is marketing and identification. The drugs should stand out, be remembered, and be distinguished from others by their appearance. Drugs are even color-matched to the corporate identity of the company or product line. Allusions are also made to the ingredients or the clinical picture. For example, tablets with herbal active ingredients are colored green and iron tablets are additionally colored red. Aesthetics and design play a role. Colored remedies are supposed to look more beautiful than white or colorless ones. In addition, it is believed that the pharmacological effects can be influenced by the colors (color psychology). A sleeping pill is dyed light blue so that the color itself is calming. Finally, drugs can contain dyes so that they are recognized and not abused. The benzodiazepine flunitrazepam (Rohypnol) contains a blue dye so that it cannot be put in drinks as a so-called “date rape drug”.
Examples
- The green color of Vicks MediNait syrup and Zeller Relaxation tablets comes from a mixture of quinoline yellow (yellow) and indigocarmine (blue).
- Viagra tablets are colored blue with indigocarmine.
- Flibanserin (Addyi), also known as “Pink Viagra”, is colored pink with iron oxide and titanium dioxide.
- Erythrosine used to color Dolocyl tablets pink.
- Bucco Tantum contains the red dyes azorubin and ponceau 4R.
- Voltaren Dolo Liquid Caps contain quinoline yellow.
Adverse effects
Dyes can cause allergic reactions and intolerance reactions (pseudoallergies). Like other additives, dyes in foods and medicines are very often criticized. Side effects of medicines can sometimes be attributed to the dyes rather than the active ingredients.
Special features
Some active ingredients are themselves colored, and the corresponding drugs do not contain dyes. These include, for example, activated charcoal (black), eosin (red), riboflavin (yellow, orange), and zinc oxide (white).
