Drugs Flashcards
Neostigmine
Treatment of mysathenia graves
Suxamethonium
Anaesthetic agent
Suxamethonium is a depolarising NEUROMUSCULAR BLOCKING DRUG
- it acts by binding to and activating the receptor, at first causing muscle contraction, then paralysis
Recuronium
Rocuronium is a non-depolarising NEUROMUSCULAR BLOCKING DRUG, acting as an antagonist the post-synaptic receptor and leaving fewer receptors available for acetylcholine
Sodium valporate
First line therapy for generalised seizures. It works by increasing GABA activity.
P450 inhibitor
Adverse effect: gastrointestinal: nausea increased appetite and WEIGHT GAIN alopecia: regrowth may be curly ataxia tremor hepatotoxicity pancreatitis thrombocytopaenia teratogenic hyponatraemia hyperammonemic encephalopathy: L-carnitine may be used as treatment if this develops
Pyridostigmine
Long acting. anti cholinesterase inhibitor
- reduces the breakdown of acetylcholine in the neuromuscular junction, temporarily improving symptoms of myasthenia gravis
betahistine
prevent meniere’s
prochlorperazine
treat acute attack of meniere’s
Triptans
For migraines
Used first-line in combination therapy with an NSAID or paracetamol.
Prescribing points
should be taken as soon as possible after the onset of headache, rather than at onset of aura
oral, orodispersible, nasal spray and subcutaneous injections are available
Adverse effects
‘triptan sensations’ - tingling, heat, tightness (e.g. throat and chest), heaviness, pressure
Contraindications
patients with a history of, or significant risk factors for, ischaemic heart disease or cerebrovascular disease
Baclofen
MS
painful involuntary contractions of the leg muscles
and for MND - muscle spasticity and cramps
Symmetrical tremor with Parkinsonism features …
Rarely caused by idiopathic Parkinson’s disease
Ondansetron
Antiemetic
Used mainly in the management of chemotherapy-related nausea.
Mainly acts in the chemoreceptor trigger zone area of the medulla oblongata.
Adverse effects:
constipation is common
prolonged QT interval
Antipsychotics indications
1) Urgent treatment of severe PSYCHOMOTOR AGITATION that is causing dangerous or violent behaviour, or to calm patients to permit assessment.
2) SCHIZOPHRENIA, particularly when the metabolic side effects of second-generation (atypical) antipsychotics are likely to be problematic.
3) BIPOLAR DISORDER, particularly in acute episodes of mania or hypomania.
4) NAUSEA and VOMITING, particularly in the palliative care setting
Antipsychotics - Mechanisms of action
Antipsychotic drugs BLOCK POST-SYNAPTIC DOPAMINE D2 RECEPTORS.
There are three main dopaminergic pathways in the central nervous system. The mesolimbic/mesocortical pathway runs between the midbrain and the limbic system/frontal cortex. D2 blockade in this pathway is probably the main determinant of antipsychotic effect, but this is incompletely understood. The nigrostriatal pathway connects the substantia nigra with the corpus striatum of the basal ganglia. The tuberohypophyseal pathway connects the hypothalamus with the pituitary gland. D2 receptors are also found in the chemoreceptor trigger zone, where blockade accounts for their use in nausea and vomiting. All antipsychotics, but particularly chlorpromazine, have some sedative effect. This may be beneficial in the context of acute psychomotor agitation
Antipsychotics- Important adverse effects
Extrapyramidal effects – movement abnormalities that arise from D2 blockade in the nigrostriatal pathway – are the main drawback of first-generation antipsychotics. They take several forms: acute dystonic reactions are involuntary parkinsonian movements or muscle spasms; akathisia is a state of inner restlessness; and neuroleptic malignant syndrome is rare but life-threatening side effect characterised by rigidity, confusion, autonomic dysregulation and pyrexia. These all tend to occur early in treatment. By contrast, tardive dyskinesia is a late adverse effect (tardive, late), occurring after months or years of therapy. This comprises movements that are pointless, involuntary and repetitive (e.g. lip smacking). It is disabling and may not resolve on stopping treatment. Other adverse effects include drowsiness, hypotension, QT-interval prolongation (and consequent arrhythmias), erectile dysfunction, and symptoms arising from hyperprolactinaemia due to tuberohypophyseal D2 blockade (e.g. menstrual disturbance, galactorrhoea and breast pain).
Antipsychotics - warnings
- Elderly patients are particularly sensitive to antipsychotics, so start with lower doses. Antipsychotics should ideally be avoided in dementia, as they may increase the risk of death and stroke.
They should be avoided if possible in - Parkinson’s disease due to their extrapyramidal effects.
