What Are the Treatments for ARSACS Muscle Spasticity?

Currently, there is no cure for Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS), so treatment for muscle spasticity focuses on managing symptoms to maximize your comfort and quality of life ^[1][2]. For severe muscle stiffness and spasms, the standard of care includes oral medications like baclofen to reduce tightness, gabapentin for nerve pain and cramps, and localized botulinum toxin (Botox) injections for specific problem areas ^[3][4][5]. However, treating ARSACS requires a careful “balancing act”—doctors must relieve painful stiffness without taking away the muscle tone that helps you stand and walk ^[6].

Oral Medications: Baclofen, Gabapentin, and Alternatives

For many patients, oral medications are the first step in managing muscle stiffness and cramps.

• Baclofen: This widely used muscle relaxant works in the spinal cord to decrease muscle spasms and tightness ^[3][7]. Because the dose must be increased very slowly, it can take several weeks or months to find the right amount. High doses can cause side effects like sedation, fatigue, and muscle weakness (a decrease in muscle strength) ^[8]. It is critical that you never stop taking baclofen abruptly, as this can trigger a severe withdrawal syndrome ^[9][10].
• Gabapentin: ARSACS can cause painful muscle cramps and neuropathic pain (shooting or burning pain caused by nerve damage) ^[4]. Gabapentin calms overactive nerves and is often used to manage these painful symptoms ^[11]. Important warning: Gabapentin can commonly cause dizziness and sleepiness, which may temporarily worsen your ataxia and increase your risk of falling.
• Other Options: If baclofen or gabapentin are not well-tolerated, your doctor may suggest other oral muscle relaxants, such as tizanidine, to help find the right balance for your body.

Targeted Relief: Botulinum Toxin Injections

Because oral medications circulate through your entire body, they can sometimes cause too much overall weakness. When spasticity is severe in just a few specific areas, botulinum neurotoxin type A (BoNT-A)—commonly known as Botox—can be an excellent alternative ^[5].

Botox is injected directly into the tightest, most problematic muscles to block the nerve signals causing the spasm ^[12]. This provides localized relief without making the rest of your body feel weak or tired. However, Botox is not a permanent fix; the effects typically wear off, requiring repeat injections every 3 to 4 months. Side effects are usually minor but can include localized pain at the injection site or temporary, excessive weakness in the injected muscle.

The Clinical Balancing Act: Spasticity vs. Weakness

The most critical conversation you will have with your neurologist involves the trade-off between treating spasticity and maintaining your mobility.

While muscle stiffness is uncomfortable, it often acts as a natural brace. In ARSACS, patients have underlying muscle weakness and poor coordination (ataxia). The spasticity provides a “functional tone” that makes the legs rigid enough to support the body’s weight ^[6][13].

If anti-spasticity medications are given at too high a dose, they strip away this functional tone. Your legs may become too relaxed and weak, which can cause your knees to buckle, significantly worsen your ataxia, and increase your risk of falling ^[6]. Therefore, the goal of medication is not to eliminate spasticity entirely, but to reduce it just enough to improve comfort and flexibility without compromising your ability to stand and walk.

Combining Treatments with Physical Therapy

Medications are rarely enough on their own. The most effective approach pairs pharmacological treatments with specialized physical therapy. Regular stretching and strengthening exercises help maintain joint flexibility. Additionally, mobility training—such as training for the safe use of walking aids, and manual wheelchair skills training for those who use wheelchairs—ensures you can safely navigate your environment and maintain your independence ^[14][15].