Transcript Anti-depressants

Anti-depressants
Or What When
Dr Bruce Davies
www.bradfordvts.co.uk
Range
 Tricyclics
 Tetracyclics
 SSRI
 SNRI
 MAOI
 Oddities
 Adjuvants
Factors Influencing Choice
 Features of illness, e.g.
agitation, hypersomia
 Suicide risk
 Other therapy
 Other illness.
 Side effects
 Cost
 Special problems e.g.
Age, driving,
pregnancy
Drug Failure
 Non compliance.
 Inadequate dosage.
 Other drugs e.g. alcohol, caffeine.
 Unresolved outside problems.
 Up to 25% failure even if above
don’t apply.
Tricyclics
Amitryptyline
 Potent sedative
 Weight gain ++
 Anticholinergic ++
 Most researched
 150mg / day
(Therapeutic in 95%
of adults)
Clomipramine
 Similar side effects
to amitryptyline.
 Said to be best for
obsessional
symptoms.
 150mg / day
Tricyclics
Dothiepin
 Sedative
 Same side effects
as amitryptyline.
 By far and away
the most toxic
antidepressant.
 150 mg / day
Imipramine
 Stimulant
 Anticholinergic ++
 150 mg/ day
Tricyclics
Lofepramine
 Least toxic TCA.
 Minimal sedative
side effects.
 Anticholinergic +
 Doubts about
efficacy.
 210 mg / day
Protriptyline
 Stimulant.
 Anticholinergic +
 40mg / day
Tetracyclics
Maprotiline
 Similar side effect
profile to
amitryptyline.
 Seizures severe in
overdose.
 150 mg /day
Mianserin
 Good safety in
overdose.
 Few sedative or
anticholinergic
properties.
 ? Agranulocytosis
risk
 90 mg / day
SSRI
 First choice in
elderly.
 First choice if
heart disease.
 First choice if
suicide risk.
 More expensive.
?
Side effects
 Like TCA reduce
with time.
 Gut problems
predominate.
 Flat dose response
curve – so no need
to titrate dose
upwards.
SSRI
Citalopram
Few
interactions
Fluoxetine
Sedation –
Skin s/e
Fluvoxamine Gut s/e +
Most
expensive
Anxiety +
Cheapest
Insomnia -
20 mg /day
Paroxetine
Sedation +
Sertraline
Diarrhoea
Withdrawal 20 mg /day
problems ?
50 mg /day
20-80 mg
/day
200 mg /day
SSNRI
Venlafaxine
 Selective Serotonin and noradrenaline
reuptake inhibitor – like amitryptyline.
 Few other effects – unlike amitryptyline.
 75-150mg / day minimum
 Dry mouth, somnolence, high BP, nausea,
headache and dizziness.
MAOI
 The old ones block peripheral
MAOI ( B ) and central MAOI (A)
so a low tyramine diet is needed. ?
Obsolete.
Moclobemide.
 Only MAOI-A.
 ? Role.
 ? Special place in anxiety disorder.
 300-600mg / day.
Oddities
Trazodone.
 Unique structure.
 Low cardiotoxicity, few
anticholinergic side effects.
 Drowsiness +.
 Nausea.
 150 mg /day.
Oddities
Tryptophan
 Natural amino acid - Serotonin
precursor.
 Eosinophilia-myalgia syndrome,
Hospital initiation only.
 Adjuvant to others ?
Flupenthixol
 Some doubts as to efficacy.
 Fast action
 1 mg / day
Adjuvants and Combinations
 Realm of
specialists
 Lithium,
carbamazepine
 Mixtures i.e. SSRI
and TCA
 Dangerous – need
expert supervision
Anxiety
 Usually worth trying a
antidepressant.
 May be useful to avoid
the stimulant ones !
 May need higher doses.
 Initiation may lead to
paradoxical increase in
symptoms. ? Cover with
short course of anxiolytic.
Anxiety
 ? Role of
benzodiazepines.
 ? Beta-blockers.
Buspirone.
 Some efficacy, but
small.
 Slow onset, 2-4
weeks.
DSM - IV
Duration > 2 weeks
Depressed mood or Marked loss of interest
or pleasure in normal activities
Plus 4 of:
i. Significant change in weight
ii. Significant change in sleep pattern
iii. Agitation or retardation
iv. Fatigue or loss of energy
v. Guilt / worthlessness
vi. Can’t concentrate or make decisions
vii.Thoughts of death or suicide
Incidence Of Depression:
2000 Patients
100 - major
100 - minor
200 subclinical
Depression. In 50% of patients it
may not be acknowledged.
ICD - 10
Patient has low mood:
1) How bad is it and how long has it
been going on?
2) Have you lost interest in things?
3) Are you more tired than usual?
ICD - 10
 Mild
Two criteria from 1-3 and 2 others.
 Moderate
Two criteria from 1-3 and 3-4 others or a
yes to question 5.
 Severe
Most of the criteria in severe form
especially questions 5 & 9.
BUT BUT BUT
 But there is a lot
more than the
drugs.
 The use of other
therapies is
equally important.
 The doctor may be
the best drug.
 Availability is
often the limit to
other treatment
methods.
Based On
 BNF June 2000.
 Depression in General Practice.
Tylee, Priest & Roberts. Pub. Martin
Dunitz. 1996.
 GP Psychotropic Handbook. S
Bazire. Quay Books. 1995.
 Basic Notes in Psychiatry. Michael
Levi. Kluwer Books. 1997.