Psychiatric Drugs Flashcards
Neuropathic pain treatment
First line;
Only 1 at a time;
- Gabapentin
- Amitriptyline (10-75mg at night)
- Pregabalan
- Duloxetine (SNRI)
Rescue therapy;
- Tramadol
Localised;
- Capsaicin topical (Axsain)
Tricyclic Antidepressants (TCAs)
Mechanism
Serotonin-Noradrenaline Reuptake Inhibitors (SNRI)
- Blocks +Serotonin reuptake Transporter
- Blocks ++Noradrenaline reuptake Transporter
Additionally
- a-Adrenergic receptor
- Postural hypotension/ dizziness
- Histamine receptor
- Sedation
- Muscarinic acetylcholine receptor
- Blurred vision, dry mouth & constipation
TCAs
Examples + Indications
Largely not used for depression now.
Amitryptiline (10mg to 75mg)
- Neuropathic pain
- Prophylaxis Tension headache (tightband bilat, no aura)
Nortryptyline
- 2nd line: Prophylaxis Tension headache
- Parkinson’s Depression+Anxiety
More sedative: Amitryptyline
Less sedative: Imipramine, Nortriptyline
Less antimuscarinic SE: Lofepramine, Trazodone
TCAs
COUNCILLING
Common, usually settle;
- a-Adrenergic receptor
- Postural hypotension, nausea & dizziness
- Histamine receptor
- Sedation
- Muscarinic acetylcholine receptor
- Blurred vision, dry mouth & constipation
OK in pregnancy & breastfeeding (except Doxepin)
SSRI
Mechanism
Selective Serotonin Reuptake Inhibitors
- Block serotonin reuptake!
SSRI
SSRI of choice for;
- Depression
- Generally
- Post MI?
- Young people?
- OCD
- GAD
- Breastfeeding
- On anti-epileptic medication
- Bulimia nervosa
- Menopause without HRT
Depression
- 1st. Citalopram or Fluoxetine
- Post-MI: Sertraline
- Young people: Fluoxetine
OCD: 1st. Fluoxetine
Anxiety: Sertraline
Breastfeeding: Sertraline
Anti-epileptic medication: Citalopram (least likely to pharmokinetically react)
Bulimia nervosa: Fluoxetine
Menopause without HRT: Fluoxetine
NB: Others often used, only bold are fixed.
SSRI
COUNCILLING
Side effects - Usually resolve/ few wks!
- GI: Nausea + Constipation/ Diarrhoea 1/10
- Dizziness + headache
- Sexual Dysfunction 60% (low libido & delayed orgasm)
- CI pregnancy + (ideally) breastfeeding
- HYPOnatraemia first 30d
- Bleeding (inhibit 5HT from PLTs..)
- QTc prolongation → Torsades (esp citalopram)
All anti-depressants;
- initial Increased suicidal ideation until treatment starts working - KEEP TAKING!
- Discontinuation symptoms (phase)
SSRI
Monitoring
2wks (1wk if higher risk), review;
- Symptoms (subside in few wks)
- initial Suicidal ideation (subsides also)
- ECG: Long QTc
- U+Es: HYPOnatraemia
SSRI
Discontinuation Symptoms
Discontinuation symptoms onset
- Phase out over 4wks
- Especially paroxetine
- Not Fluoxetine
Symptoms include
- Mood change
- Restlessness/ cant sleep
- GI
SNRI
Mechanism
Serotonin–norepinephrine reuptake inhibitors
- Blocks ++Serotonin reuptake Transporter
- Blocks +Noradrenaline reuptake Transporter
aka non-tricyclic SNRIs
SNRI
Examples + Indications
Switiching in Depression
Venlafaxine
- Menopause without HRT vasomotor
Duloxetine
- Neuropathic pain
SNRI
COUNCILLING
SPECIFIC SNRI (Venlafaxine, Duloxetine)
- HyPER- or hypo-tensive
- Cardiotoxic in OD
- Glycaemic Control (monitor DM)
+ SSRI
NARI
Mechanism
NorAdrenaline Reuptake Inhibitor
NRI
Examples & Indications
Reboxetine
Depression
NRI
COUNCILLING
Reboxetine;
Mild & resolve
- GI: Nausea + Constipation/ Diarrhoea 1/10
- Dizziness + headache
- Sweating
+ SSRI but very rare
MAOI
Mechanism
Mono-Amine Oxidase Inhibitor
MAO-A (therapeutic) and MAO-B
-
A selective reversible
Meclobemide -
A+B non-selective irreversible
Phenelzine -
B selective irreversible
Selegiline, rasagiline
A - serotonin, noradrenaline, dopamine
B - dopamine +
MAOI
Examples + Indications
Depression
- Phenelzine (A+B)
- Meclobemide (A)
Parkinsons
- Selegilline, Rasagilline (B)
MAOI
COUNCILLING
Moclobemide
- MAO-A selective, reversible, competitive
- Milder and transient SEs
Phenelzine
- MAO-A+B non-selective, irreversible, non-competitive
SEs
- Postural hypotension
- HYPERtension + Tyrosine
- Muscarinic: Dry mouth, blurred vision, urinary retention
- CNS: Restlessness, insomnia
- Hx of Agitation/ Excition prominent - CI or add Benzodiazepine/2-3wks
NaSSA
Mechanism
Noradrenergic and Specific Serotinergic Antidepressent
- Blocks Noradrenaline a2-auto and heteroceptors (both sides)
- Prevents negative feedback on 5HT and noradrenaline neurotransmission
- ALSO block 5HT2 and 3 increasing 5HT1 transmission
NaSSA
Examples + Indications
Mirtazapine
NaSSA
COUNCILLING
- Weight gain + inc appetite
- Drowsiness (transient, not dose-related)
-
Agranulocytosis (rare, reversible, stop)
- REPORT sore throat!
1st Gen. antipsychotics
Mechanism
D2 antagonist;
- mesoCortical ⇒ Helps neg. symptoms
- mesoLimbic system ⇒ Helps positive symptoms
- Nigro-Striatal ⇒ Muscular extra-pyramidal SEs
- Tubero-infundibular ⇒ High Prolactin SEs
- Chemoreceptor trigger zone ⇒ Antiemetic
Additionally blocked;
- Muscarinic1
- Histamine1 ⇒ Sedation, allergies
- Alpha1
1st Gen antipsychotics
Examples
- Chlorpromazine
- Haloperidol
- Fluphenazine (depot)
- Clophenthixol
1st Gen antipsychotics
SEs + Management of them
- *D2 Blocked;**
- *Nigro-Striatal** ⇒ Muscular extra-pyramidal SEs
- Short term
- Acute dystonia
- Occulogyric crisis (agitation, eyes up)
- Akathisia
- Medium
- Parkinsonism
- Long term
- Tardive dyskinesia
- Treatment: Procyclidine
Tubero-infundibular ⇒ High Prolactin SEs
- Amenorrhoea (linked to osteoporosis)
- Gynaecomastia
- Galactorrhoea
Serious: Neuroleptic Malignant Syndrome (other card)
Additionally blocked;
-
Muscarinic1
- Constipation, dry mouth, blurred vision
-
Histamine1
- Sedation
-
Alpha1
- Postural hypotension, Ejaculation problem
Haloperidol: LONG QT Syndrome
ALL Phenothiazines “ZINES”: Fetal anomalies by extra 4/1000 (chlorpromazine)
Atypical or 2nd Gen antipsychotics
Mechanism
Blocks
- D2
- 5HT2a (more than D2)
Also
- Alpha1
- Histamine1
- Muscarinic1
aka Serotonin-Dopamine antagonists
Atypical or 2nd Gen antipsychotics
- Olanzapine
- Quetiapine
- Clozapine (actually D4) (refractory schizophrenia)
- Resperidone
- Aripiprazole (partial dopamine agonist, sometimes called 3rd generation)
Atypical or 2nd Gen antipsychotics
SEs
Specifically Clozapine
LESS musclar/ extra-pyramidal SEs (but still occur)
MORE metabolic SEs
- Weight gain
- Potential glucose intolerance
- Potential lipids increase
Aripiprazole: LESS metabolic SEs
Risperidone: Insomnia & agitation (CNS)
Clozapine (refractory schizophrenia)
- Agranulocytosis
- Cardiotoxic
- Salivation (M4)
- CNS
Illicit drugs that increase dopamine
- Cocaine
- Amphetamines
- L-dopa
Neuroleptic Malignant Syndrome
- Cause
- Signs and symptoms
- Investigations
- Treatment
Cause
- Genetic varient of D2 receptor: Abnormal blockade in striatum & hypothalamus
- RF: Change in medications, any psychiatric condition
Signs and symptoms
- Fluctuating BP
- Flutuating consciousness/ Delirium
- Rigidity + extra-pyramidal SEs
- Fever + Sweating
Investigations
- CK HIGH!
- Leucocytes high
- Abnormal LFTs
Treatment
- Withdraw treatment immediately (death!)
- Dopamine agonist (may take 2wks)
Antipsychotic monitoring
All require;
- BP + pulse (Alpha1)
- weight + height
- Bloods
- Glucose/ HbA1c and Lipid profile (esp 2nd gen)
- LFTs + U&Es
- Prolactin (Tubero-infundibular)
- ECG:
Clozapine: FBC (neutropenia/ agranulocytosis) 2ndary care
NMS suspected: CK
TCA
Overdose S+Sx
- Arrhythmias - ECG
- Sinus tachycardia
- Wide QRS ⇒ >0.1 Seizures ⇒ >0.16 VT/VF
- Prolonged QT
- Seizures
- Metabolic acidosis
- Coma
TCA
Overdose management
- Acutely: Activated charcoal
- Acidosis?: IV Bicarbonate (lower seizure/ arrythmia risk)
- IV Lipid emulsion
DO NOT;
- Dialysis ineffective
- Class 1 (a+c) ⇒ Prolong depolarisation
- Class 3 ⇒ Prolong QT
Lithium
Mechanism + Indications
Lithium ⇒ Mood stabiliser
- Mania
- Hypomania
- Prophylaxis for Bipolar + Recurrent depression
- Reduces aggression and self injury
Lithium
COUNCILING
Plasma level
- Measure 12hr after last dose
- Effective >0.4mmol/L, OPTIMAL 0.6-0.75mmol/L
- Toxic >1.5mmol/L ⇒ SEs
Patient NEED;
- Information booklet
- Record book
- Lithium Alert Card
SEs
- GI (D+N+V)
- Kidney impairment (polyuria, polydipsia)
- Weight gain
- HyPOthyroidism, hyPERparathyroidism
- CNS (Course tremor, weakness, ataxia, twitching)
- ⇒ Seizure, coma, death
- Teratogenic, benefit>risk?: Cardiac defects
Plasma concentration + drugs;
- +ACEi ⇒ x4
- +ThiazideD ⇒ x4
- +NSAIDs ⇒ Unpredictable
Lithium Overdose management
- Mild-mod: Volune resus Normal saline
- Severe: Haemodialysis
Sodium bicarb?
