Diltiazem and Sun Exposure.
They reported four such cases in African American women who presented over a 2-year period. The patients' mean age was 62 years, and all had been taking the long-acting formulation of the drug (Cardizem CD) for 6-11 months before the eruption occurred.
The hyperpigmentation appeared as reticulated, blue-gray patches on the glabella, malar eminences, neck, upper chest, and distal aspects of the arms and hands.
There was notable sparing of the nasolabial folds, submental regions, and posterior auricular triangles.
"These features are noticeably different than those of other drug- or chemical-induced photodistributed hyperpigmentation," the investigators said (Arch. Dermatol. 137:179-82, 2001).
The condition resolved in all four women after the drug was discontinued and replaced by antihypertensive agents other than calcium channel blockers.