48 - How to avoid1416,18

How to avoid14–16,18

Depression and anxiety disorders CHAPTER 3 Clinical relevance14,15 The symptoms of a withdrawal reaction may be mistaken for a relapse of illness or the emergence of a new physical illness,16 leading to unnecessary investigations or reintroduction of the antidepressant. Symptoms may be severe enough to interfere with daily functioning and those who have experienced discontinuation symptoms may reason (perhaps understandably) that antidepressants are ‘addictive’ and not wish to accept treatment. There is also evidence of emergent suicidal thoughts on discontinuation with paroxetine.17 Who is at risk?10,14–16,18 Although anyone can experience discontinuation symptoms, the risk is increased in those prescribed short half-­life drugs (e.g. paroxetine, venlafaxine),7 particularly if they do not take them regularly. Two-­thirds of patients prescribed antidepressants skip a few doses from time to time,19 and many patients stop their antidepressant abruptly.20 The risk is also increased in those who have been taking antidepressants for 8 weeks or longer,21 those taking antidepressants at higher doses, those who have developed anxiety symptoms at the start of antidepressant therapy (particularly with SSRIs), those receiving other centrally acting medication (e.g. antihypertensives, antihistamines, antipsychotics), children and adolescents,7 younger patients,22 and those who have experienced withdrawal symptoms before. How to avoid14–16,18 Generally, antidepressant therapy should be discontinued gradually.6 The shorter the half-­life of the drug, the more important it is that this rule is followed. The end of the taper may need to be slower, as symptoms may not appear until the reduction in the total daily dosage of the antidepressant is (proportionately) substantial. Patients receiving MAOIs may need to be tapered over a longer period. Tranylcypromine may be particularly Table 3.8  (Continued) Antidepressant type Symptoms Serotonin modulators (vortioxetine, vilazodone) None reported,10 although these are relatively new antidepressants with less clinical experience. Shared pharmacological actions with other antidepressants (SSRIs) so possibility of withdrawal symptoms cannot be discounted.10 TCAs General somatic and GI distress, sleep disturbances characterised by initial and middle insomnia or excessively vivid and frightening dreams, akathisia or parkinsonism, hypomania or mania, cardiac arrhythmia10 Trazodone Hypomania, anxiety, restless sleep, nightmares, depersonalisation, formication, headache10 * Tranylcypromine may have amfetamine-­like properties at higher doses12 and therefore could be associated with a true ‘withdrawal syndrome’. Delirium may occur.13 NaSSA, noradrenergic and specific serotonergic antidepressant; RIMA, reversible inhibitor of monoamine oxidase A; TCA, tricyclic antidepressant.