What kind of antidepressive drug is preferably given to a patient with a history of exanthema when

Fråga: What kind of antidepressive drug is preferably given to a patient with a history of exanthema when treated with venlafaxine?

The exanthema worsened when treated with antihistamines. Do antihistamines and venlafaxine interact to produce skin reactions?

A 52-year-old woman with depression has been treated with venlafaxine for a long period of time. In April she developed an exanthema, tried an antihistamine but got worse. The patient called an unknown adviser who told her that the combination of antihistamines and antidepressants may worsen exanthemas. According to the physician she looked like she had pocks all over her body. She stopped the venlafaxine treatment and the exanthema slowly disappeared during the summer. She retried clomipramine despite earlier problems with a dry mouth while administration of this drug. Two weeks before this question was asked she stopped clomipramine treatment and retried venlafaxine. Once again she developed a pock like exanthema all over the body.

Sammanfattning: There are no indications in the literature that a combination of venlafaxine and anti-histamines may potentiate the intensity of adverse events through a metabolic interaction. Both of these drugs may independently cause adverse skin reactions. The worsening of the exanthema after administration of an antihistamine may be caused by the additive effect of each drug separately. There is also a possibility that the antihistamine caused a photosensitivity reaction as it was administered during the summer season. It is probable that venlafaxine was the reason for the exanthema as re-exposition led to an identical skin reaction. There are no reported cross-reactions for venlafaxine and therefore that choice of a new antidepressive drug is open. If a tricyclic antidepressant is not preferable due to anticholinergic symtoms, sertraline and reboxetine are alternatives not reported to give skin reactions.

Svar: Similar questions have been discussed in Drugline earlier (1-6).

Some antihistamines; eg cetirizine, clemastine, cyklicine, cyproheptadine, terfenadine,loratadine and acrivastine, may induce skin reactions eg photohypersensitivity reactions, exanthema and urticaria (2-5, 7, 9-12). For venlafaxine exanthema and ekkymosis are reported as frequent adverse events (> 1/100) and alopeci, photosensitivity and urticaria as less frequent (1/1000 1/100) (6, 7). Sertraline and reboxetine are the only antidepressants not yet reported to give adverse skin reactions (7). There have been 30 reports of adverse skin reactions by venlafaxine (including six cases of exanthema, three of itching, four urticaria, five defluvium, four photosensibility), reported to SADRAC (The Swedish Adverse Drug Reactions Advisory Committee).

We have found no reports concerning suspected drug interactions between venlafaxine and antihistamines in the literature. Neither are there any reports of cross-reactions between venlafaxine and other substances.

We recommend this case be reported to SADRAC. 1 Drugline no 08712 (year 1992)
2 Drugline no 11416 (year 1995)
3 Drugline no 11151 (year 1994)
4 Drugline no 09834 (year 1993)
5 Drugline no 09831 (year 1993)
6 Drugline no 13089 (year 1996)
7 FASS 1999 (The Swedish catalogue of approved medical products)

8 Owen JR, Nemeroff CB: New antidepressants and the cytochrome P450 system: foxuc on venlafaxine, nefazodone, and mirtazapine. Depress Anxiety 1998; 7(suppl 1): 24-32 9 Stingeni L, Caraffini S, Agostinelli D, Ricci F, Lisi P: Maculopapular and urticarial eruption from cetirizine. Contact Dermatitis 1997; 37: 249-250