What Are Photosensitive Drugs?

The stability of drugs can be altered by several factors. Photosensitive drugs contain drugs that must be protected from light, both natural and artificial. Otherwise, many of the components will deteriorate and the drug will lose its clinical effectiveness.

That’s why these drugs are packaged in opaque containers to prevent light penetration. For example, some injectable forms of photosensitive drugs are presented in amber ampoules or vials for protection purposes.

It is recommended that these photosensitive drugs are always kept in their containers until use. If they are removed from containers, an effective method is to cover them with aluminum foil or other opaque paper that does not allow light to pass through.

Studies on photosensitive drugs

The lack of published studies on the stability of photosensitive drugs made it necessary to carry out internal reviews in hospitals about this type of drug.

It is important that laboratories carry out photosensitivity studies of their products and that the results are recorded on the technical data sheet. That way, it will be easier to have information in a more accessible and reliable way. Knowing all the information about photosensitive medications is an important part of drug stability, and for that it must be required by law.

Light protection measures

Depending on the type of medication, the light protection measures will be different.

For inhaled, topical, ophthalmic, and optically administered medications, and for liquid and parenterally administered medications, light protection measures are classified as follows:

• Do not protect from light : they are non-photosensitive drugs, with photosensitive active ingredients or without photosensitivity data, protected by a primary packaging opaque to light.
• Protect from light : includes drugs with photosensitive active ingredients whose primary packaging does not protect from light.
• Protect from light due to the absence of photosensitivity data : these are medicines that contain active ingredients for which there is no photosensitivity data and whose primary packaging does not protect from light.

On the other hand, with regard to solid oral forms, light protection measures are classified as:

• Do not protect from light : the same as for previous medications.
• Protect from light by storing in another opaque material package: includes drugs with photosensitive active ingredients or for which no information about their photosensitivity is available. Furthermore, the primary packaging does not protect from light.

Differences between photosensitive and photosensitizing drugs

Photosensitive drugs are those that can deteriorate in contact with light, natural or artificial. If they are not well stored, their physicochemical and pharmacological properties can be altered. In addition to the loss of effectiveness of the drug, exposure to light can produce toxic compounds for the body.

Although it is a common mistake, it is very important to distinguish between photosensitive and photosensitizing drugs. The latter are those that, combined with ultraviolet radiation, form new molecules that produce negative reactions to the skin.

If we were exposed to the sun under normal conditions, nothing would happen to us. But if we do this after taking a photosensitizing drug, we can get serious skin problems. These types of reactions are not well known to the general population, so it is extremely important that the doctor and pharmacist inform patients about the correct use of medications.

Conclusion

More studies are needed on the photosensitivity of medications, because today there is not much information, making work in hospitals difficult. In addition, it is possible to avoid health problems by correctly storing medications.

Lastly, remember that a photosensitive drug is not the same as a photosensitizer. Photosensitives deteriorate with light and photosensitizers are what can cause skin problems by reacting with the sun’s ultraviolet rays.