Nortriptyline (Pamelor) is a tricyclic antidepressant approved by the FDA only for the treatment of depression. However, with the introduction of SSRI family of antidepressants such as fluoxetine (Prozac) which have fewer side effects, the use of tricyclic antidepressants for depression has declined.

Tricyclic antidepressants are still in wide use, but mostly for the treatment of headaches and pain. Nortriptyline is very similar to amitriptyline (Elavil) and is thought to cause fewer and milder side effects, although this has not been proven. This could be due to the fact that amitriptyline is broken down into nortriptyline, which is the active metabolite. Amitriptyline tends to be more sedating, which can be useful in patients with insomnia.

There are no good blinded studies of nortriptyline for the prevention of migraines and they are not likely to be done. We assume it is as good as amitriptyline, although studies of amitriptyline also lack in size and scientific rigor.

There are many trials of amitriptyline and nortriptyline for various pain conditions, but they are also not up to our modern standards. Amitriptyline was approved in the US in 1961.

Besides sedation, nortriptyline can cause dry mouth, constipation, urinary retention in older patients, and other side effects. The dose to treat migraines and pain is usually lower than the dose used to treat depression. Pain and headaches sometimes respond to as little as 10 or 25 mg while for depression, the dose goes up to 100 mg and higher.

In short-term studies of major depression, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults. This is less likely to occur when treating pain, but many pain patients also experience depression.

Eptienzumab (Vyepti) was just approved by the FDA for the preventive treatment of migraine headaches. Eptinezumab is another monoclonal antibody that blocks the effect of CGRP, a chemical released during a migraine attack. It joins erenumab (Aimovig), fremanezumab (Ajovy), and galcanezumab (Emgality), three other monoclonal antibodies approved for the preventive treatment of migraine headaches.

Eptinezumab is different from the other three drugs in that it is administered intravenously. It is given every three months by an infusion over 30 minutes. The other three drugs are self-administered subcutaneously every month, although fremaezumab can be also given every 3 months.

Eptinezumab may also have a faster onset of action because it is administered intravenously and quickly reaches its peak concentration in the blood. The other three drugs take up to a week to reach their maximum concentration. The reason for such a long delay (most drugs injected subcutaneously take less than an hour to peak) is that the monoclonal antibodies are large molecules and are distributed not by blood vessels, but the slow-moving lymphatic system. On the other hand, these are preventive therapies, so the speed of onset is less critical than for abortive drugs, such as NSAIDs, triptans, and gepants (ubrogepant, rimegepant).

Theoretically, it is possible that eptinezumab could work for patients who do not respond to the other three drugs because of a better distribution of the drug and because these drugs are not identical. About 10% of my patients report significantly better response when switched from erenumab, which was first to be approved, to either fremanezumab or galcanezumab.

We don’t know yet what the drug will cost and how well the insurance companies will pay for it. All three subcutaneous drugs cost about $650 a shot and all three manufacturers offer a one-year free trial if the insurance refuses to pay. This does not apply to patients who have Medicare or Medicaid, which do not allow free trials or discount coupons. Fortunately, more and more insurers, including the government plans, are covering these drugs, albeit with some paperwork that needs to be completed by the doctor. The cost of eptinezumab will consist of two parts – the cost of the drug and the cost of the infusion.