Antidepressants for Chronic Pain: Why Do Doctors Prescribe Them & Do They Work?

Antidepressants are commonly prescribed to treat depression, but in recent years, doctors like myself have begun prescribing them for treating chronic pain. While the use of antidepressants for this purpose is becoming more common, there is still some debate over their effectiveness.

In this article, I will explore why antidepressants are prescribed for chronic pain and examine the pros and cons of using them for this purpose.

“Why is my doctor prescribing a depression drug for my pain?” Do they think it’s ‘all in my head’?”

As I gently float the idea of prescribing an antidepressant to help my next patient who suffers chronic pain every day, I wonder if that’s the thought going through their mind. These days it is becoming less often that there's a furrowed brow or a look of surprise, but even when that happens, the concern usually melts away as I explain.

I explain that choosing a medication has to be tailored to the individual and that we make treatment decisions together after a series of considerations.

What is the most common antidepressant used to treat pain?

Even though we file them all under the umbrella of "antidepressants", there’s a broad range of medications that are different to each other and have very different mechanisms of action on the mind and body. When we appreciate this, we can often find a medication most suitable for a treatment trial.

What we carefully choose can sometimes mean hitting two birds with one stone, even using some side effects as benefits. Some patients are kept awake by pain, so the side effect of drowsiness could end up being helpful.

The most common antidepressant medicines I prescribe for my patients experiencing chronic pain are amitriptyline and duloxetine.

About amitriptyline

Amitriptyline is a very old drug that’s been around since the 1960s. While predominantly used as an antidepressant since its discovery, these days it’s often used for other purposes. I most commonly prescribe this for chronic pain, nerve pain, and irritable bowel syndrome (IBS).

One of the advantages of this medication is it comes in small dosage tablets. I often start at 1/30th of the maximum dose, allowing us to start at a tiny dosage and slowly work up. Side effects are bothersome, the dry mouth being the main one, but thankfully is dose-dependent. This also means starting at very small doses allows us to minimize the negative impacts

About duloxetine

Duloxetine is an antidepressant belonging to a class called serotonin–norepinephrine reuptake inhibitors or SNRIs.

It is listed and commonly prescribed to treat depression and anxiety disorders, fibromyalgia, neuropathic pain and central sensitization. It comes in a capsule, which means we can’t cut them in half. This means it limits dosing options. I find duloxetine is worth a try for patients who, outside of their chronic pain, would also benefit from antidepressants for their mood. Occasionally I would change an existing antidepressant a patient is on over to duloxetine to try and provide pain relief.

Like amitriptyline, common side effects include dry mouth, nausea, feeling tired and occasionally, dizziness.

What do these antidepressants do?

Or more importantly, what do we want them to do? Different medications can do different things, but in this case, we’d like it to:

• Reduce overactive pain signals
• Reduce pain from damaged nerves
• Studies tell us antidepressants aren’t usually as effective for ‘physical pain’ such as a bruise or a cut

What are the prescribing considerations?

Side effects are the biggest consideration. They may include things like dry mouth, nausea, feeling tired, or sometimes feeling "out of it". Side effects may depend on the dosing - this is why we would often start with a low dose and gradually increase it.

Will antidepressants fix my pain?

Medications help some people more than others, but using them alone will not solve the problem. Chronic pain is a complex puzzle to solve, and medication is only one ingredient in a broader multifaceted management plan. It is better used as a therapy enabler, together with pain education, psychological therapy, physiotherapy, and diet and lifestyle support.

I always tell my patients that the goal of the medication is not to eradicate all pain, but rather to 'lighten the load' or act as a 'circuit breaker' in the often self-perpetuating cycle of pain. If you’re stranded in water, the medication is like a floaty that relieves the stress of treading water, so you can focus on where to swim.

How do these other therapies help with my pain?

As the saying goes, you can’t lift a table from one corner only. It’s usually the non-medication-based therapies that provide better and longer-lasting benefits, to reduce your pain, improve your function, and have more good days. If you would like to discover what these non-drug therapies are, please click through our suggested posts.

I almost always prescribe psychotherapy to go in hand with any prescriptions. Many of my patients have said that their medications helped them get into a better ‘zone’ and allows them to benefit more from psychotherapy. This then allows us to gradually take them off the medications.

Often, doctors like myself prescribe antidepressants for people without depression. Different doctors might prescribe different antidepressant drugs for different problems, to varying degrees of success.