Citalopram is generally the first medication depression and anxiety sufferers are prescribed these days; it is one of the newer, more recently tested, SSRI meds. SSRIs in general are the "in" thing right now, and citalopram is supposed to be better because in theory it has fewer side effects. In practice though it can be rather erm... exciting.
As with any SSRI, the dosage is gradually increased. Your MC will likely be given a prescription for 5mg for the first week or 2, up to 10mg for a month after than, then 15mg, then maybe 2-3 months down the line up to 20 or 25mg. I was put up to 30mg over a six month period before my GP accepted it wasn't working for me and tried another one.
For the first week, I was told to sign off work. The side effects when you first start taking the meds can be varied and quite unpleasant, and although they generally persist for up to 6 weeks (although sometimes longer), a week or 2 is presumed to be long enough for you to work out what side effects you'll get and find a workaround.
One thing- the meds info leaflets in the packets list side effects according to how common they are. General consensus amongst users is that the commonality was determined by throwing darts at a board, since the "very rare" effects seem anecdotally to be actually very common. I've bolded the ones I had to give you an idea of how much of a range people can get. Side effects can include;
feeling sick
dry mouth - I got this. Also started gurning and chewing my face like I was on ecstasy.
sleepiness
shakiness of the arms and legs
diarrhoea
headache
dizziness
visual disturbance
sleeping difficult
constipation
weakness
increased sweating
palpitations
agitation
nervousness
pins and needles
increased anxiety
problems concentrating
confusion
increased suicide risk
abnormal dreams (very common - in my support forum we often had threads about "what did you dream last night". Think vivid, bizarre fever dream adventures that seem to span whole new worlds. Bes. Side effect. Ever.)
tiredness
yarning
abnormalities of vision
migraine
memory loss
listlessness
feeling faint after standing
rapid heart rate
loss of appetite or aversion to food
increase in appetite
weight gain or loss
indigestion
stomach pain
wind
vomiting
abnormalities of taste
increased salivation
runny nose
sinusitis
impotence
reduced libido
anorgasmia
problems passing water
period pains
rash
itching
muscle pain
jerky movements
fits
ringing in the ears
false sense of wellbeing
increased sex drive
coughing
malaise
sensitivity to sunlight
changes in liver function
slow heart rate
fainting
allergic reactions
bleeding in the skin, bruising, stomach and from the vagina
increased bleeding time
changes in the salt balance in the body
hallucinations
mania
feeling of unreality - I didn't get this but apparently it is really, really common
panic attacks
production of breast milk
swelling of the lips, eyes and tongue
joint pain
Many of the side effects dissipated after a couple of weeks. The dosage is a slowly increased thing and it is normal for it to take anything up to 6 weeks before users feel any of the benefits of the medication. If the meds prove unsuitable, it is also normal for patients to be gradually weaned off citalopram and on to something else, because the withdrawal symptoms can be as bad, if not worse, than the side effects. There were times when I was coming off one med onto another and would be having withdrawal symptoms of one, side effects of another and none of the benefits of either. Fun times!
If I had to describe the "benefits" as I experienced them, it would be as a numbing effect. The panic was still there, the depressive sensations and the desire to self harm. But I felt detatched from it, numb to it. The meds weren't intended to fix me but to give me space to be rational and to have some distance from my problems whilst I sought therapy.
Oh! If for any reason you give your MC a non-SSRI like mirtazapine, side effects there are very different. I experienced violent mood swings and increased violent desires/tenencies. When things got really bad I'd disappear off to the work loos, close myself in a cubicle, and thrash around until I felt better. I'm just gald I had somewhere to go hide before I had to throw a wobbler! I also had severe difficulty waking. One time, my other half patiently encouraged me out of bed and went to make me a cuppa while I got dressed. He came back to me half-naked, asleep on the floor cuddling the clothes I'd been trying to dress into.