Polyaddiction Flashcards
Polypharmacy
The concurrent use of multiple medications by a patient
Who is at most risk of polypharmacy?
Chronic Disease Risk ≈ Increased Age
Polypharm risks (3)
- Non-adherence
-Confusion
-Incorrect storage - Drug-drug interaction
-Interfere with desired drug effect - Drug-disease interaction
- Negatively impacts on another disease/symptom
Drug-drug - schizo
speeds up metabolism:
= 50-705 of schizo patients smoke , potentially due to anti-psychotic side effects - by speeding up metabolism
Parkinson’s - drug-disease
L dopa:
antag for L=dopa (pelneristone)
Drug-Drug interactions (5)
- Prescription drug-drug interactions
- Prescription/OTC/herbal drug-drug interactions
- Prescription/illicit drug-drug interactions
- Illicit drug-drug interactions
- Drug-alcohol interactions
Alert fatigue (2)
BNF/GP/pharmacies:
see warnings to often = almost ignore/desensitised to it
= increased prescriptions - deaths
Prescription Drug-Drug interactions (4)
TRAMADOL & ANTIDEPRESSANTS: - double SSRI’s activity
SSRIs
SNRIs
TCAs
MAOIs : ↑ Serotonin (tramadol) - serotonin syndrome
Pain and depression are common co-morbidities
Clinical Practice Research Datalink
~7% of the UK pop (~4.6 million people)double
Serotonin syndrome(5)
same symptoms as MDMA overdose
Increased temp
tachycardia
agitation
tremor
etc.
Antidepressant,
Tramadol, Codeine
Prescription - studies (2)
Risk of mortality when prescribed an antidepressant alone or in combination with tramadol or an alternate opioid (codeine)
highest w/tramadol + antidepressant (40.7 deaths/1000) - even w/o codeine (3x less - 15.1)
Prescription Drug-OTC/ herbal drug-drug interactions (6)
- Reliable patient history- remembering what they are taking (i.e.barroca every morning)
- Patient understanding
of interactions
e.g. anti-histamines + benzodiazepines
peripheral histamine r = immune response
central histamine r = consciousness
benzo stabilises GABA binding site = to reduce oscillation b/w active + inactive (wobbling)
= increases affinity for GABA
- helps anxiety
-stronger doses = RD + death
PRESCRIPTION-HERBAL REMEDY INTERACTIONS (3)
- ST JOHN’S WORT & ANTIDEPRESSANTS
- DAT/SERT/NET - possible severe toxicology
Blockade & MAO inhibition?
= SS - VALERIAN & SEDATIVES(BENZODIAZEPINES & ANTI-HISTAMINES)
- Valerian acts as a sedative
= RD - MELATONIN & ANTIPSYCHOTICS
- Reduces tardive dyskinesia
Prescription illicit drug-drug interactions - meth + heroine (4)
Methadone + heroine - helping ween off heroine
Prescribed methadone
Heroin relapse (double opioids)
= overdose
- Much longer half
life than heroin - Illicit methadone ( to red. withdrawal from heroin high)
- Combined to reduce
‘come down’
=overdose
also seen in addictions to sedatives e.g. histamines
Prescription illicit drug-drug interactions - gabapentioids + opioids (6)
Gabapentin
Pregabalin
- inhib voltage gated ca2+ channels = neurotransmission
Drug user reports:
* Enhances the ‘high’
* Less heroin/opioid required (almost cost saving - 1/2 amount of heroin = inc sedation + euphoria than heroin alone)
Pregabalin:
* Enhanced bioavailability (93% vs 33-66%)
* Pregabalin absorption is much faster (1hr vs 3-4hrs)
* Gabapentin absorption is rate limited
* Enhanced affinity: 6 times more potent
illicit drug-drug interactions - stimulant co-admin (3)
Amphetamines : NA + DA
MDMA/Ecstasy: NA + DA + 5HT
Cocaine/Khat: NA + DA
