Question

What would you do next?

Taper off both drugs in both patients

Taper off both drugs in both patients while treating with antihistamines

Taper off both drugs in both patients, treat with antihistamines, and start new SSRI monotherapies once rash clears

Taper off both drugs in both patients, treat with antihistamines until rash clears, then rechallenge with different preparation of same antidepressant, if available given their initial improvements

Attending physician’s mental notes: interim follow-up visits through three months (continued)

The patients were both improving on their respective medications

If possible, and safe, would like them to be on the same, or closest similar medication next, to perpetuate their initial responses to their last medication

Sometimes changing preparation of a drug may alleviate allergies

• – Certain tablets or capsules may have dyes or sugars that create the allergic response

  • The allergy is not caused by the antidepressant molecule itself, but rather by the dyes or fillers

  • However, if the allergy is to the specific drug molecule, the allergic response will happen again when the drug is restarted

Case outcome: interim follow-up visits through six months

Patient #1

• – Is tapered off his generic citalopram, and given antihistamines until his rash clears

• – He agrees to try the brand name citalopram (Celexa) as it will have the same drug molecule but different fillers

• – He is titrated to 40 mg/d

• – This allows for gradual improvement in some of his MDD symptoms again

• – No rash develops

• – He was likely allergic to the dye or fillers in the previous generic preparation

Patient #2

• – Is tapered off her purple dye-colored bupropion-IR tablets

• – Is given antihistamines until her rash and swelling clears

• – Pharmacy is called and asked to locate an all-white, non-colored preparation of bupropion-SR

  • This assumes that the patient was allergic to only the dye of bupropion-IR, not the drug molecule

• – Patient is placed on low-dose, white 100 mg tablet, SR preparation

  • Rash and facial swelling returns

  • Her antidepressant is discontinued

  • She is presumed allergic to the bupropion molecule itself

  • No further rechallenges with any preparation are warranted

Attending physician’s mental notes: interim follow-up visits through six months

Sometimes allergies are due to the medication’s molecule itself, such as in Patient #2, and the medication should be avoided in the future, regardless of preparation (immediate versus slow release, brand name versus generic)

• – This allergy to the medication should be listed in the patient’s chart

Sometimes allergies are due to the fillers (excipients, dyes, sugars, slow-release polymers) inside a tablet or capsule, not the drug molecule, as seen in Patient #1

• – In these situations, rechallenging is worthwhile, if the patient was improving on the initial antidepressant and tolerating it well

• – If the type of dye causing the reaction can be determined or triangulated, it should be listed specifically as the allergen in the patient’s chart

Some drugs that are more prone to skin rashes and disruptions, however, are likely not worth a rechallenge, such as lamotrigine (Lamictal), topiramate (Topamax), modafinil (Provigil), etc., as the risk of serious or even life-threatening rashes is higher