Propranolol, interaction with lithium

The authors attribute the bradycardia to an interaction with lithium as the low dose of propranolol was considered unlikely to cause bradycardia alone. They also point out that both drugs affect the movement of calcium across cell membranes, which could account for the decreased contraction rate of the heart muscle, and thus bradycardia in this patient. They suggest careful monitoring in elderly patients with atherosclerotic cardiovascular problems. ... 

Clinically important, potentially hazardous interactions with benztropine, eucalyptus, fluoxetine, lithium, methotrexate, nilotinib, propranolol, sulpiride... 

Clinically important, potentially hazardous interactions with albuterol, alcohol, clonidine, corticosteroids, danazol, diuretics, epinephrine, estrogens, isoniazid, lithium, oral contraceptives, pentamidine, phenothiazines, propranolol, somatropin, terbutaline, thyroid... 

A 79-year-old woman with a long history of bipolar disorder, stabilised on lithium carbonate and doxepin 200 mg at bedtime and also taking propranolol, was given tamoxifen 20 mg daily after a mastectomy for breast cancer. It was noted that her total blood levels of doxepin and its major metabolite were reduced by about 25% over the next 11 months. The control of her depression remained unchanged. The reasons for this apparent interaction are not known. The manufacturer of tamoxifen has another undetailed and isolated report of a possible interaction. ... 

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