Page 58 - Demo

CONTINUING PROFESSIONAL DEVELOPMENT
MEDICATION REVIEW
Withdrawalsymptomsappearedwithin1–5 days following abrupt or tapered discontinuation, lasting between 1 and 14 weeks.6 The most common withdrawal symptoms associated with sertraline were fatigue, gait instability, vertigo and flu-like symptoms.6
In the community setting, recommended methods of switching from an SSRI are to gradually taper
the dose of the initial antidepressant then have a washout period of five half-lives, or to have 2–4 days (longer for fluoxetine) break before introducing
the next antidepressant at the usual starting dose5. For sertraline, it has been recommended to reduce the daily dose by 50 mg every 5–7 days until
the daily dose is 50 mg (or even 25 mg) before discontinuation.4 Other options for switching antidepressants such as direct switch or cross- tapering are generally unsuitable for general practice. See Table 4 for descriptions of different switching methods, the level of risk and appropriate clinical settings.5
Serotonin syndrome can occur during antidepressant switching. Symptoms comprise hyperreflexia, clonus, tremor, incoordination, changed mental state, shivering, sweating, fever, diarrhoea. Any additive serotonergic properties of two antidepressants should be considered first, as unrecognised or untreated serotonin syndrome
can be fatal.7 Particular caution is required for fluoxetine, vortioxetine, duloxetine, agomelatine and fluvoxamine.5 Fluoxetine has a long half-life, so a washoutperiodofaround5 weeksmayberequired if switching to clomipramine, fluvoxamine or MAOIs, to reduce the risk of serotonin syndrome.5
In Mrs LC’s case, she is suffering from anxiety, irritability, sleep disturbances, a possible worsening of depression and bouts of crying. She has had falls that may be attributed to dizziness, ataxia, light- headedness, gait instability or vertigo. Untreated urinary tract infections can cause deterioration in mental health and falls in older people, but this was excluded by the nursing staff observations. Mrs LC is most likely suffering from serotonin withdrawal syndrome as a result of stopping sertraline abruptly. This withdrawal syndrome may have been diminished due to the intermittent administration of sertraline in error by the nursing staff. Whilst not recognising the link with sertraline discontinuation, the GP has attempted to treat the withdrawal symptoms with risperidone. The use of atypical antipsychotics in dementia is not recommended, due to the increased risk of cerebrovascular events, including stroke.1 Mrs LC is already at an increased risk of stroke due to her diabetes.
Table3.SignsandsymptomsofwithdrawalfromSSRIs
System involved
Symptoms
Affective
Anxiety, agitation, tension, panic, depression, intensification of suicidal ideation, irritability, impulsiveness, aggression, anger, bouts of crying, mood swings, derealisation, depersonalisation
Balance
Dizziness, ataxia, light-headedness, gait instability, vertigo
Cognitive
Confusion, decreased concentration, amnesia
Gastrointestinal
Nausea, vomiting, diarrhoea, anorexia, abdominal pain
General
Flu-like symptoms, fatigue, weakness, tiredness, headache, tachycardia, dyspnoea
Neuromotor
Tremor, myoclonus, ataxia, muscle rigidity, jerkiness, muscle aches, facial numbness
Psychotic
Visual and auditory hallucinations
Sensory
Paraesthesia, electric-shock sensations, myalgias, neuralgias, tinnitus, altered taste, pruritus
Sexual
Genital hypersensitivity, premature ejaculation
Sleep
Insomnia, vivid dreams, nightmares, hypersomnia, lethargy
Vasomotor
Sweating, flushing, chills
Visual
Visual changes, blurred vision
Adapted from Fava6
Table 4. Techniques for switching from one antidepressant to another
Method
Comments
Conservative switch
• Gradually reduce first antidepressant
• Stop first antidepressant
• Have a drug-free washout period of five half-
lives of first antidepressant
• Start second antidepressant at usual starting
dose
• Appropriate for general practice • Low risk of drug interactions
• Discontinuation symptoms may
occur
Moderate switch
• Gradually reduce first antidepressant
• Stop first antidepressant
• Have a drug-free washout period of 2–4 days • Startsecondantidepressantatalowdose
• Appropriate for general practice • Low risk of drug interactions
• Discontinuation symptoms may
occur
Direct switch
• Stop first antidepressant
• Start second antidepressant the next day at
usual therapeutic dose
• Requires clinical expertise
• Discontinuation symptoms likely,
dependent on antidepressant
• Risk of drug interactions
dependent on antidepressant
• Only appropriate in selected
instances, such as swapping one short half-life antidepressant to another
Cross-taper switch
• Gradually reduce first antidepressant
• Start second antidepressant at a low dose during the time that first antidepressant is
being reduced
• Patient is taking both antidepressants
simultaneously
• Stop first antidepressant
• Increase dose of the second antidepressant
to a therapeutic dose after first antidepressant is stopped
• Requires clinical expertise
• Use for patients at high risk of
relapse
• Risk of drug interactions
• Increased adverse effects from
combination of antidepressants
• Only appropriate with selected drug and clinical circumstances
56 Australian Pharmacist January 2017 I ©Pharmaceutical Society of Australia Ltd.
Adapted from Keks5