ER will be a capsule -- the non extended release are tablets you can split. Your experience of missing a couple of days is very consistent with what I've had over the years - especially the weird dreams...the nausea, etc can also happen.

I don't believe there is any particular correlation between dosage and the magnitude or duration of withdrawal symptoms....I didn't really have any symptoms until I got down to 37.5mg (from 150mg - both in the ER form) and then those symptoms were worse once I tapered to zero after about 3 weeks at 37.5. My taper was supposed to happen more quickly - but I chose to slow it down because of the withdrawal symptoms and my difficulty getting work done.

Can't offer you any advice on your concerns over SAD in the winter and a taper....SAD has never been part of my pathology. However, re; being past menopause -- one can still have menopause like symptoms years after menopause officially occurs....it's like post-perimenopause...but my guess is any menopause-like symptoms will be less frequent and intense.

There's probably no downside to taking the pills indefinitely - but that is a question for your physician. Although I recently read that there is potentially a correlation between SNRIs (Effexor, Cymbalta) and glaucoma risk. This came up when my ophthalmologist decided to watch me more closely for glaucoma. I've been suspect for decades because of my anatomy - so it will be interesting to see what if any changes he sees after I've been off Effexor for 6 months...but I think the data is pretty spotty at this point - and it wouldn't change whether or not he would start treatment.

@mtcashel ,
The following was found at https://www.everydayhealth.com/drugs/effexor--
Common side effects of Effexor XR (venlafaxine) may include hot flashes, dizziness and/or drowsiness, tiredness, yawning, headaches, nausea, vomiting, gas, stomach pain, diarrhea, constipation, heartburn, burping, dry mouth, changes in taste, loss of appetite and weight loss, nightmares, muscle tightness, frequent urination, difficulty urinating, changes in sexual desire or ability, twitching, shaking of a part of the body, pain, burning numbness, or tingling in part of the body, sore throat, chills, or other signs of infection, ringing in the ears and enlarged pupils. Other side effects with Effexor include sinusitis (sinus inflammation), infection, flu-like syndrome, shortness of breath and cough.

Effexor has been associated with some more serious side effects, including seizures, an increased risk of bleeding, increased blood pressure and elevated cholesterol levels.

Venlafaxine can interact with other prescription, or nonprescription medications in ways that hinder its effectiveness, or bring on serious side effects. So, if you develop a condition that requires a medication that doesn't work well with Effexor, you'd probably have to come off (perhaps in a hurry).

Venlafaxine may cause harm to a developing fetus. Newborns whose mothers took venlafaxine in the last three months of pregnancy were reported to experience feeding and breathing problems, and seizures, shakes, jitters, and constant crying immediately following delivery. For women who take antidepressants in the second and third trimesters of pregnancy, there is a risk that the baby can be born prematurely, according to the National Alliance on Mental Illness.

Like many other antidepressants, use of venlafaxine has been associated with weight gain. Weight gain caused by venlafaxine may be due to fluid retention, lack of exercise, increased appetite, or other factors.

A common side effect is blurred vision, occurring in up to 6 percent of patients taking the medication. Those with glaucoma, or high risk of developing glaucoma should be monitored carefully.

Most SNRIs, including Effexor, can cause sexual side effects, such as delayed orgasm, reduced libido, and erectile dysfunction.

Some folks (not just older ones) are also concerned that they are experiencing short- and long-term memory issues. Patients taking Effexor should contact their health care provider right away for any memory loss. Memory loss may be a sign of a potentially serious side effect called hyponatremia (low blood sodium). Other symptoms of hyponatremia include headache, difficulty concentrating, confusion, weakness, and unsteadiness.

Dry mouth is a side effect of Effexor. This can be very detrimental to your dental health as you may develop cavities easily and other issues.

According to Lexi-Comp, the dosage of Effexor (venlafaxine) should be reduced in patients that have mild to moderate liver disease. Liver problems occur rarely in patients taking Effexor. Fatty liver, hepatic necrosis, hepatic failure and hepatitis have been reported in less than 1% of studied patients taking Effexor.

Intestinal obstruction is listed as a rare side effect in people taking the medication.

I read elsewhere something about increase in fractures in older people and loss of bone calcium.

Despite all this, if you are not really having any issues with Effexor, are in good health, possible pregnancy is not an issue and you can afford to pay for the drug (if you lose your insurance, or it quits covering this drug), you might want to stay on Effexor. I wasn't having any problems with my 25mg dose of Effexor (although the hot flashes were long gone), it only cost $25 for a six-month supply and I very rarely missed, or forgot a dose. If I had known I would develop akathisia even with a slow tapering, I think I would have left well enough alone and stayed on Effexor.