Really bad dizziness and feeling faint

[Falacience]

I’m currently 2.5 weeks on Prozac/fluoxetine. First week or so was sheer hell in terms of increased anxiety. Had a couple of good days at the start of this week but suddenly have been hit with severe dizziness/light head. It feels like my whole brain is swimming. I’m feeling jittery and weak too, and have bad nausea but I haven’t been sick yet.

Went to out of hours GP last night and was told my temperature, blood sugar, blood pressure and urine were all fine. Is it normal to get these symptoms suddenly (and for two full days so far)? It feels so bad that I keep thinking something dangerous is happening to me. Struggling to accept that I may actually have a bug/flu as it just seems too coincidental.

Any insight would be welcomed! And any tips on how to reduce the dizziness - water and rehydration sachets don’t seem to be working.

[panic_down_under]

I'm currently 2.5 weeks on Prozac/fluoxetine. First week or so was sheer hell in terms of increased anxiety. Had a couple of good days at the start of this week but suddenly have been hit with severe dizziness/light head.

The increased anxiety, dizziness, lightheartedness and nausea are typical initial side-effects of serotonergic antidepressants (ADs), i.e. SSRIs, SNRIs and some TCAs, cause by the initial spike in serotonin activity, both within the brain and other organs. Serotonin is not just a brain neurotransmitter. It has many functions throughout the body including in the regulation of blood vessel tone - constriction and dilation - and wound repair. The gut is often also greatly effected as it is by far the most serotonergic organ producing more than 90% of the body's serotonin. The brain makes and uses less than 2%.

The side-effects usually begin to diminish after a while as bio-feedback mechanisms kick-in to reduce serotonin synthesis and expression, but may reoccur for a short while after dose increases.

I keep thinking something dangerous is happening to me

While the side-effects can be unpleasant and scary they are rarely indicators of physical harm.

I'm feeling jittery and weak too, and have bad nausea but I haven't been sick yet.

Ginger and/or vitamin B6 supplements may ease nausea and maybe the dizziness too. If they don't help then ask your doctor to prescribe an antiemetic and mention the other side-effects too as there are ways of managing them.

Struggling to accept that I may actually have a bug/flu as it just seems too coincidental.

It likely is the fluoxetine, but if you do have the flu or another infection then this may be exacerbating your symptoms, especially the uptick in anxiety. Anxiety and depression are the emotional expressions of a physical brain dysfunction caused by a type of auto-immune reaction atrophying parts of the hippocampal regions of the brain and symptoms often worsen when the immune system ramps up to fight an infection.

any tips on how to reduce the dizziness - water and rehydration sachets don't seem to be working.

I'm guessing you were prescribed 20mg which is the usual starting dose for depression but is often too high for those with anxiety. If so, I suggest you talk to the prescribing doctor about cutting the dose to 10mg for the first 2-3 weeks.