Neostigmine and Glycopyrrolate for the Treatment of Headache After Dural Puncture

Hypothesis: Neostigmine and glycopyrrolate will reduce the proportion of postpartum women with a PDPH requiring EBP who developed a PDPH after accidental dural puncture with a Tuohy needle.

Background: The post dural puncture headache (PDPH) is a well-documented complication of dural puncture. Depending on a number of factors, the overall incidence of PDPH following dural puncture with an epidural Tuohy needle is typically around 50%, but can be as high as 70% for certain populations.

The headache is characterized as frontal or occipital in nature, with a typical onset of 6-72 hours after dural puncture. It is normally exacerbated by the upright position and improved by the supine position. Associated symptoms may include photophobia, nausea, vomiting, dizziness, tinnitus, neck stiffness, decreased hearing and visual changes. These symptoms tend to be extremely debilitating in affected patients, severely limiting their functional capacity until the resolution of the headache. The compromise is even greater in postpartum women who also need to care for a newborn, as the time after birth is important for forming attachment and encompasses many new obligations for the new mother.

The treatment of the PDPH often begins with conservative treatment including supportive therapies such as hydration, bed rest, acetaminophen, NSAIDs, and oral opioids. In addition, some evidence exists for the use of caffeine. While these do not hasten recovery, they may improve symptoms. For PDPH of all etiologies, 72% will resolve spontaneously in 7 days and 89% by 14 days.

For patients with moderate to severe symptoms or long lasting headaches, the gold standard for treatment of headaches that do not resolve is the epidural blood patch (EBP). This treatment has been shown to be effective in 70-98% of patients. However, it has numerous contraindications including fever, infection, coagulopathy, active neurological disease, patient refusal. In addition, a potential complication is yet another dural puncture. Also, while the EBP is generally very safe, it is an invasive procedure with its own complications; it has been associated with very rare but serious complications including: moderate long-lasting backache, meningitis, epidural abscess formation, epidural hematoma formation, and neurologic deficit development.

The use of neostigmine and atropine in the treatment of PDPH was first described in a randomized placebo-controlled trial in 2018. The addition of neostigmine and atropine to conservative treatment for PDPH resulted in all 41 patients in the treatment group reporting a visual analog scale (NRS) score ≤ 3 after 2 doses, no recurrence of headache, and none receiving EBP. Seven out of 42 (15.9%) patients in the placebo group reported a persistent NRS ≥ 5 and all received EBP. Postulated mechanisms of action of neostigmine and atropine in the treatment of PDPH include increased CSF volume and cerebral vasoconstriction. Patients enrolled in this study developed a PDPH after spinal anesthesia using a 22-gauge Quincke needle. The effects of neostigmine and atropine on PDPH resulting from accidental dural puncture with a larger-bore, 17-gauge epidural Tuohy needle are unknown.

Neostigmine and atropine, when given concomitantly, antagonize each other's adverse effects resulting in a favorable safety profile. The most common adverse effects reported include blurred vision, dry mouth, abdominal cramps, muscle twitches, and urinary urgency - all of which were transient. Additionally, simultaneous administration of neostigmine and atropine likely have a net neutral effect on oxytocin release and likely do not affect lactation or breastfeeding for the mother. Both neostigmine and atropine are excreted in very small amounts in the breastmilk and are unlikely to affect the breastfed infant more than transiently.

In the available literature, the main driver of this improvement is thought to be from the cholinergic effects of neostigmine. When unopposed, these cholinergic effects are known to cause side effects such as muscle cramping. The main purpose of adding of atropine in the original study - as well as the addition of an anticholinergic in most clinical practice applications - to neostigmine is to counteract these potential cholinergic adverse reactions. Glycopyrrolate is the anticholinergic of choice for use with neostigmine as a muscle relaxant reversal agent. This is because glycopyrrolate has a pharmacokinetic profile that mirrors neostigmine and is able to more effectively to eliminate the cholinergic effects in patients who receive neostigmine over the duration of the neostigmine pharmacologic effect.

Number of Participants: Enrollment of 36 with goal of 18 evaluable patients

Design: Prospective Pilot Study

Recruitment: In person contact by OB Anesthesia resident, OB Anesthesia fellow, Anesthesia consultant, or Research Coordinator

Recruitment process: Patients will be identified as at risk on the labor and delivery ward after they have experienced a known dural puncture with a Tuohy needle. Patients will be assessed daily while in the hospital for signs and symptoms of a PDPH. If patient meets criteria after dural puncture (a positional headache after known dural puncture, worsened by the upright position, NRS score of ≥ 4), they will be informed of the study procedures, given time to ask questions regarding procedures, and decide if they consent to participation. Patients will also be counseled on the risks and benefits of EBP and can elect to proceed with EBP at any point in the study.

Intervention:

Patients with a PDPH after documented accidental dural puncture with a Tuohy needle and a NRS score of ≥ 4 will receive a slow infusion of 20 μg/kg neostigmine and 4 μg/kg glycopyrrolate IV given over 10 minutes. Patients will be monitored with blood pressure measurements every 3 minutes along with continuous EKG and pulse oximetry during the infusion and for 20 minutes after completion of the infusion. This regimen is repeated every 8 hours for a maximum of 3 doses. Treatments continue until a NRS score ≤ 3 is achieved or the patient elects to proceed with an epidural blood patch. Patients also receive conservative PDPH management which includes encouraging oral hydration, encouraging oral caffeine consumption in patients who regularly consume caffeine, 1 g acetaminophen every 6 hours, and 600 mg ibuprofen every 6 hours. Oxycodone 5-10 mg every 4 hours PRN may be utilized for postoperative pain.

Safety Monitoring: Patients receiving the intervention will be monitored during and after the intervention for abdominal or muscle cramps, blurred vision, dry mouth, or urinary urgency by the OB anesthesia provider administering the intervention. They will be instructed to call the research PI if they have any of these complications. Patients will also be monitored with blood pressure measurements every 3 minutes along with continuous EKG and pulse oximetry during the infusion and for 20 minutes after completion of the infusion.

Consent process: Consent will be obtained after identification of a PDPH after documented accidental dural puncture with a Tuohy needle and a NRS score of ≥ 4 in the patient's hospital room. Patients will be given sufficient time to ask any questions to the attending/resident anesthesiologist and research personnel related to the procedure and this research study.