Brief Answer:
Excess weight gain could be due to depression, hypothyroidism and drugs

Detailed Answer:
Hi, thanks for asking from HCM for your health related queries

I can understand your concern. Coming straight to your doubts-

1) The significant weight gain in last 8 years occurred due to multiple causes. Hypothyroid states is one of main reason for weight gain. Antidepressants can also cause weight gain but you have used the drugs for short periods only. Hypothyroid states increase the risk of depression which in turn result in altered dietary habits and might cause weight gain. This weight gain further aggravates depression and results in a vicious cycle and thus significant weight gain.

2) Allegra is an antihistaminic drug with some adrenaline blocking actions also. The drug has not much serious drug interactions with Venlafaxine. In fact the drug should potentiate the action of Venlafaxine. But I failed to find any specific studies that show any serious concern while taking these drugs together. No significant pharmacological relation between Allegra and Venlafaxine.

Thanks. Take care. If you have more doubts please ask again.

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Brief Answer:
Yes the drug might cause gain in weight.

Detailed Answer:
Hello thanks for asking again

Yes the drug might cause gain in weight. Though the drug is an advanced antihistaminic drug still the drug can cause gain in weight. But very severe weight gain usually doesn't occur in patients taking it. A lot of patients of mine are on this drug but weight gain was not very important issue for them.

Thanks.

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