17 - PSYCHOSTIMULANTS Flashcards
INDICATIONS
Narcolepsy Depression in the elderly, senile dementia, Alzheimer´s disease Epilepsy Fibromyalgia Chronic fatigue syndrome Restless leg syndrome Syncope Cranial traumatisms Postanaesthetic shock Morbid obesity Hyperactivity in children (with or without attention deficit).
CLASSIFICATION
AMPHETAMINES AND RELATED SUBSTANCES
METHYLXANTINES
NATURAL METHAMPHETAMINES
CATHINONE AND EPHEDRINE
SYNTHETIC AMPHETAMINES
AMPHETAMINE
METHAMPHETAMINE
METHYLFENIDATE
EPHEDRINE
AGONISTAS ADRENÉRGICOS DE ACCIÓN DIRECTA
LIBERADORES
INHIBIDORES DE LA CAPTACIÓN
INHIBIDORES DE LA MAO7COMT
ANFETAMINAS, TIRAMINA
COCAÍNA
PARGILINA, ENTACAPONE
AMPHETAMINE
Half-life:10h, latency 30-60 min
Indications: narcolepsy, ADHD or antikinetosis.
METAMPHETAMINE
Analogue of amphetamine, more
rapid action and shorter half-life (5h).
Abuse: students, sportsmen, professional drivers
CONSUMPTION OF AMPHETAMINES AND METAMPHETAMINES
CHRONIC USE
Chronic use leads to supersensitivity of postsinaptic
D2 R which explains depressive symptomatology after
abrupt interruption of the consumption.
CONSUMPTION OF AMPHETAMINES AND METAMPHETAMINES
EFFECTS
Mood improvement, increased energy and alertness, decreased appetite, euphoria.
Nervousness, tachycardia, tremor, fever, insomnia, hypertension, increased
glycaemia. Formication (the feeling of having insects crawling under one´s skin).
CONSUMPTION OF AMPHETAMINES AND METAMPHETAMINES
INTOXICATION
Intoxication: central and peripheral sympathetic hyperstimulation with
cardiovascular risk, neuronal alteration such as mania, anxiety, aggressiveness or
hypersexuality (Amphetamine psychosis)
AMPHETAMINES AND RELATED SUBSTANCES, MECHANISM
Noradrenergic and dopaminergic system.
- Enhance the release of these neurotransmitters
- Inhibit the re-uptake of these neurotransmitters
- Stimulate adrenergic receptors directly (agonists)
AMPHETAMINES AND RELATED SUBSTANCES, TOLERANCE
They create tolerance (greater in the peripheral effects and in anorexia)
Dependence (absence of a clear physical withdrawal syndrome, only 5% of the
consumers reach complete dependence).
AMPHETAMINES AND RELATED SUBSTANCES, PHARAMACOKINETICS
Pharmacokinetics: efficient absorption p.o. They easily cross the BBB.
Amphetamine: not metabolized neither by MAO nor by COMT prolonged action.
Hepatic metabolism, 30-50% is eliminated through the urine in the active form.
Half life: ap.10h (2-30h, depending on the diuresis and urinary pH).
p.o, i.v., also smoked or sniffed.
NON- AMPHETAMINIC DRUGS
Methylfenidate and permolin
METHYLFENIDATE
(piperidine derivative, of immediate release (Rubifen®), duration:
2-4h, or sustained release (Concerta®, 10-12 h), osmotic mechanism of release:
the capsule contains three chambers, two of which have different methylfenidate
concentrations, while the third one consists of a polymer whichs expands in
contact with liquids.
