What are photosensitive medications?

The stability of medications can be altered by many different factors. Specialties containing photosensitive medications should be protected from light, both natural and artificial. Otherwise, many of the components will deteriorate and the drug will lose clinical efficacy.

It is for this reason that these types of medicines are packaged in opaque containers, to prevent the light from penetrating. For example, some injectable forms of photosensitive medications are presented in ampoules or in topaz colored vials for this purpose.

It is recommended that these photosensitive medications are always stored in their containers until they are going to be administered. If they are removed from the 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 medications

The lack of published studies on the stability of photosensitive drugs has made it necessary to perform internal reviews in hospitals About this type of medication.

It is important that laboratories carry out photosensitivity studies of their products and that the results are recorded in the technical file. In this way, it will be easier to have information in a more accessible and reliable way. Knowing all the information on photosensitive medications is an important part of the stability of medications and, for this, it is necessary that the law requires it.

Light protection measures

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

In the case of medications administered by inhalation, topical, ophthalmic and otic, and of liquid forms and parenteral administration medications, Light protection measures are classified as follows:

  • Do not protect from light (NPL): are non-photosensitive medications and medications, either with photosensitive active ingredients or without photosensitivity data, protected by a light-opaque primary conditioning.
  • Protect from light (PL): includes medicines with photosensitive active ingredients whose primary conditioning does not protect from light.
  • Protect from light due to lack of photosensitivity data (PL-ND): these are medicines that contain active ingredients for which photosensitivity data are not available and whose primary conditioning does not protect from light.

On the other hand, as for solid oral forms, the light protection measures are classified as:

  • Not protect from light: in the same way as for previous medications.
  • Protect from light by repackaging with opaque materials (PLR): includes medicines with photosensitive active ingredients or for which information on their photosensitivity is not available. In addition, the primary conditioning does not protect from light.

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Differences between photosensitive and photosensitizing medications

Photosensitive medications are those that can deteriorate upon contact with light, both natural and artificial. If they are not well preserved, their physicochemical and pharmacological properties can be altered. In addition to the loss of efficacy of the drug, toxic compounds can be produced with the body with light.

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

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

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More studies on photosensitivity are necessary of medications because today there is not much information, which makes it difficult to work in hospitals. In addition, health problems related to the proper storage of medications could be prevented.

Finally, remember that a photosensitive drug is not the same as a photosensitizer. The photosensitive ones deteriorate with the light and the photosensitizers are those that can produce cutaneous problems when reacting with the ultraviolet rays of the sun.