FEATURE A NEUROLOGICAL Statement


It’s probably true to say that pharmacists aren’t the first professionals who are thought of when it comes to the treatment of neurological conditions. However, whilst the diagnosis side of this family of conditions should be left for professionals who are highly trained in this particular area, the pharmacist’s expertise in medicines makes them a key player in ensuring that patients receive the care they need to keep their conditions under control.


W


hat are neurological conditions? Before we can start to think about certain


conditions in more depth, it’s important for us to have a good grounding in what these conditions are, what they affect, and how they come about, in general.


According to the World Health Organisation, neurological conditions (or disorders) are diseases of the central and peripheral nervous system (including the brain, spinal cord, cranial and peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscles). Such disorders can come about as a result of many occurrences, including trauma, infection, malnutrition, and


Carbamazepine


genetic predisposition, or a combination of various factors. Whilst pharmacists are unlikely to make the comparison, it’s important to remember that these conditions are very different to mental health conditions, and should be regarded as such. This is an important point when it comes to counseling patients who may be distressed (however wrongly) about this, and any attached stigma.


In terms of the size of the issue, hundreds of millions of people are affected by neurological conditions worldwide. The numbers of deaths caused by these conditions are also staggering – for example, approximately 6.2 million people die a year from stroke alone.


Gabapentin/ Pregabalin


Lamotrigine


As with many conditions, socioeconomic status plays a big factor in prevalence and death rates – over 80% of fatalities from neurological conditions come about in low to middle-income countries(1)


. The


reasons for such an outcome are multifactorial – people from such areas are known to partake in less healthy lifestyles than wealthier counterparts, which can predispose such conditions, and those with lesser income have reduced accessibility to health insurance, meaning that they may not be able to receive the treatments they need, allowing acceleration of the condition at much higher rates.


Moreover, in many areas worldwide, there is still a paucity of funding into


Levetiracetam Phenobarbital


the study of serious neurological conditions, especially when compared to other conditions such as asthma or diabetes(2)


.


Due to the extent of the term “neurological disorder,” it’s not possible to provide detail on all of these conditions here. Rather, we’ll focus on two of the most prevalent conditions – epilepsy, which affects 50 million patients worldwide, and Alzheimer’s disease, which is by far the leading cause of dementia, causing 60-70% of the 36 million cases of dementia globally(1)


.


Epilepsy In short, epilepsy is a grouping of neurological disorders that are


Table 1. Information on commonly used antiepileptic drugs. Information adapted from BNF 70, and www.drugbank.ca Name


Indication


Drug of choice in simple and complex focal seizures, first line in generalized tonic-clonic seizures, and adjuvant in focal seizures when monotherapy ineffective.


Mechanism of Action


Inhibits sustained repetitive neuron firing by blocking use-dependent sodium channels.


Treatment of focal seizures with/without secondary generalisation.


First-line treatment of focal, primary and secondary generalised tonic- clonic seizures. Also licensed for typical absence seizures in children.


Reduction of the axon excitability, via interaction with cortical neurons at auxillary subunits of voltage-sensitive calcium channels. Gabapentin increases the synaptic concentration of GABA, enhances GABA responses at non-synaptic sites in neuronal tissues, and reduces the release of monoamine neurotransmitters, reducing excitation.


Notes


Modified release preparation should be offered to reduce side effect risk; patient should be maintained on specific branded or generic product. Can exacerbate tonic, atonic, myoclonic and absence seizures – not recommended in these conditions.


Not recommended for patients who suffer from tonic, atonic, absence or myoclonic seizures.


Inhibition of voltage- sensitive sodium channels and/or calcium channels, thereby stabilising neuronal membranes, and reducing electrical activity.


Licensed for monotherapy/adjunct ive therapy of focal seizures with/without generalisation amongst others, and a number of unlicensed indications.


Exact mechanism of action unknown. Suggested that stimulation of synaptic vesicle protein 2A (Sv2A), is responsible, leading to inhibition of neurotransmitter release.


Effective in the treatment of tonic- clonic and focal seizures. Can also be tried for treatment of atypical absence seizures, atonic and tonic seizure.


Acts on GABA receptors, increasing synaptic inhibition. Elevates seizure threshold and reduces the spread of seizure activity.


Phenytoin


Licensed for tonic- clonic and focal seizures.


Sodium Valproate All forms of epilepsy.


Phenytoin acts on sodium channels on the neuronal cell membrane, limiting the spread of seizure activity and reducing seizure propagation.


Binds to and inhibits GABA transaminase. Anticonvulsant activity may be related to increased brain concentrations of (GABA), an inhibitory neurotransmitter in the CNS.


Myoclonic seizures can be worsened by lamotrigine. Can cause serious rashes in children. Can be used both as a sole treatment and as an adjunctive treatment – take care with other antiepileptics as they can cause increase/decrease in plasma lamotrigine levels.


N/A


Can have a sedative effect when used in adults, and behavioural disturbances and hyperkinesia in children.


May exacerbate absence or myoclonic seizures. Has a narrow therapeutic index, and small increases in dose might bring about acute toxic side- effects, due to non-linear dose/plasma level relationship. Preparations containing phenytoin sodium are not bioequivalent to those containing phenytoin base, so care must be taken if patient switched between preparations.


58 pharmacyinfocus.co.uk


Available in M/R forms such as Epilim® Chrono® - patients may need to be maintained on a specific manufacturer’s product, be it branded or generic.


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