1. Letter to Editor
Antiepileptic
Drugs (AEDs) remain the foundation of long-term epilepsy management, yet their
consequences often receive minimal clinical attention. Over the last two
decades, substantial evidence has emerged linking chronic AED therapy,
particularly with enzyme-inducing and valproate-based agents, to impaired bone
mineralization and increased fracture risk. Despite this, bone health
assessment remains notably absent from standard epilepsy care pathways in many
low- and middle-income countries.
Zhong1,
et al. showed in a
meta-analysis of 19 reports that patients who had been on valproate monotherapy
have a statistically significant decrease in Bone Mineral Density (BMD) when
compared with matched controls, with loss further increasing after 36 months of
uninterrupted therapy. The results were uniform across the adult and pediatric
populations, emphasizing that skeletal weakness occurs early in the course of
treatment. Long-term exposure to valproate inhibits osteoblast activity and
collagen production, changing bone microarchitecture and resulting in brittle
bones even in young persons1.
Systematic
review by Griepp2 et al. brought
together the wider range of AED effects on bone, showing that both traditional
and newer drugs adversely affect calcium homeostasis and vitamin D balance. Enzyme-inducing
AEDs like phenytoin, carbamazepine and phenobarbital promote vitamin D
catabolism via cytochrome P450 induction, whereas valproate disrupts bone
matrix protein production. The cumulative effect, osteopenia, osteoporosis and
increased fracture risk, represents a preventable, chronic burden to patients
already potentially beset by physical and social disability from epilepsy.
At a
regional level, Nadeem and Nadeem emphasized that vitamin D deficiency is
already epidemic in South Asians, reaching over half of Pakistan's adults3. In such environments, long-term use of
AEDs adds to an underlying nutritional deficiency, which makes the patient
prone to premature skeletal fragility. Socio-cultural practices, restricted
exposure to sunlight and absence of dietary fortification add to this risk. The
authors recommend context-based protocols for vitamin D monitoring and
supplementation in the management of epilepsy in the setting of
resource-constrained environments3.
Clinically,
the implications are simple but poorly applied. Baseline and regular checks on
serum calcium, phosphate, alkaline phosphatase and vitamin D should be standard
for patients placed on AEDs for more than six months. Dual-Energy X-Ray
Absorptiometry (DEXA) screening, if available, can detect early
demineralization of bones prior to the development of irreversible changes.
Calcium and vitamin D supplementation, lifestyle therapy and weight-bearing
exercise are the foundation of prevention. Notably, clinicians should
reevaluate the long-term need for valproate or enzyme-inducing therapy in
patients with other risk factors for osteoporosis and use alternative AEDs when
feasible.
This problem has implications beyond the individual patient to healthcare economics. Fragility fractures have high costs of rehabilitation and surgery, especially in developing countries where preventive surveillance is cheap by comparison. Incorporation of bone health assessment into guidelines for epilepsy management is an inexpensive, high-reward intervention. As our knowledge of AED-induced metabolic effects increases, so must our clinical awareness.
2. Conclusion
In summary, the skeletal consequences of long-term AED therapy represent a preventable iatrogenic condition. Preventive screening, early supplementation and heightened clinician awareness can collectively minimize osteopenia and fractures in individuals with epilepsy. It is thus essential for neurologists, family physicians and policy-makers to prioritize bone health as a standard component of epilepsy care, one that is both evidence-based and morally obligatory.