Doxepin and Quetiapine interaction

Potential additive effects when used in combination with CNS depressants or sedating antihistamines.

Although behaviors such as "sleep-driving" may occur with hypnotics alone at therapeutic doses, the use of alcohol and other CNS depressants with hypnotics appears to increase the risk of such behaviors, as does the use of hypnotics at doses exceeding the maximum recommended dose.

When taken with SILENOR, the sedative effects of alcoholic beverages, sedating antihistamines, and other CNS depressants may be potentiated [s ee Warnings and Precautions (5.2) and Drug Interactions (7.3 , 7.4) ].

Patients should be cautioned about potential additive effects of SILENOR used in combination with CNS depressants or sedating antihistamines [s ee Warnings and Precautions (5.2) and Drug Interactions (7.4) ].

CNS Depressants and Sedating Antihistamines: Sedative effects may be increased with doxepin.

• Anticholinergic (antimuscarinic) Effects: Use with caution with other anticholinergic drugs and in patients with urinary retention, prostatic hypertrophy, or constipation (5.20)

It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder.

Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever, and primary central nervous system (CNS) pathology.

This contributes to anticholinergic adverse reactions when SEROQUEL XR is used at therapeutic doses, taken concomitantly with other anticholinergic medications, or taken in overdose.

SEROQUEL XR should be used with caution in patients receiving medications having anticholinergic (antimuscarinic) effects [see Drug Interactions (7.1) , Overdosage (10.1) , and Clinical Pharmacology (12.1) ] .