SUMATRIPTAN (TOSYMRA)
- Relevant Drug Information
Drug class – Antimigraine agents/Serotonin 5-HT-Receptor Agonists
Mechanism of action – sumatriptan is a selective 5-HT1B and 5-HT1D receptor agonist in the cranial arteries. It results in vasoconstriction and anti-inflammatory effects which are normally associated with antidromic neuronal transmission and cause the relief of migraine headache.
Drug administration and dosage
Oral route: For the treatment of migraine headache, the drug can be given as an oral tablet of 25mg, 50mg or 100mg with fluids where the maximum per dose should not exceed 100mg. additional doses can be given every 2 hours as to when needed. The maximum oral daily dose is 200mg/day and evidence has shown that its combination with naproxen gives better results.
Parenteral route: Sumatriptan is given as 6mg subcutaneous injection with an autoinjector and this can be repeated at one-hour intervals or more. The maximum injectable dose is 12mg SC every 24 hours.
Drug interactions
Serious drug-drug interactions can occur between sumatriptan and citalopram (benzodiazepine), ondansetron (antiemetic), linezolid (antibiotic), venlafaxine and rosagiline (antidepressants) and an alternative should be used in these cases. Additionally, the drug is contraindicated where particular drugs are being used, for example, almotriptan, bromocriptine, cabergoline, ergotamine, naratriptan and zolmitriptan.
Lab effects/Interference
Sumatriptan is not known to interfere with the routinely applied clinical laboratory investigations.
Special considerations
The drug doses may be reduced when adverse reactions occur. Additionally, the oral doses should not exceed 50mg/dose when the patient has mild to moderate hepatic impairment. Subcutaneous doses do not require dosage adjustments but should be used with caution. The drug should NEVER be given through IV. When the patient has a severe hepatic impairment, then sumatriptan is contraindicated.
The drug should not be administered in cases where the patient has certain vascular diseases, for example, TIA, MI, stroke, angina, and ischemic bowel disease. It should also not be given to patients with uncontrolled hypertension, those with a history of hypersensitivity to the drug or component, and any history of coronary artery disease.
Potential side effects/Adverse effects/Toxicities
The commonest adverse event of sumatriptan is the injection site reaction, which is nearly 86% occurrence. Other common events include paresthesia, dizziness and hot sensation. Uncommon side effects include chest discomfort, neck tightness, diaphoresis, cold sensation, sore throat, dysphagia abdominal distress and malaise.
- Patient Education
Nursing management
It involves monitoring the vital signs especially the blood pressure and pulse, due to sumatriptan’s action that might cause arrhythmias or MI. Nurses also observe the patent for changes in severity, the duration of the character of the headache to safeguard against potential meningitis. Additionally, the neurological status of the patient is monitored by regularly performing neuro-checks and monitoring consciousness levels. Nurses also monitor laboratory tests including BUN, liver enzymes, CBC, urinalysis and creatinine clearance for determination of liver and kidney functions.
Patient Education Considerations
The patients should be instructed and advised to:
- Monitor their vital signs (blood pressure and pulse) while using home equipment properly.
- Be aware of the warning signs of stroke and disease like meningitis
- Know that dizziness can occur due to the drug’s action in CNS or possible ischemia
- Report immediately any side effects experienced
- To observe laboratory testing requirements for the liver enzymes
Patient assessment
Before administration of sumatriptan, the nurse takes a detailed health history of the patient including cardiac studies, allergies, hematologic, laboratory, GIT, and renal studies.
The drug history of the patient is also taken to assess the patterns of use of analgesics and possible hypersensitivity.
- Assess for LOC and any pain before sumatriptan administration and after.
- Assess for infectious agents and any other factor that could cause pain or inflammation
- Assess the response to therapy and the need for additional drug doses
- Assess avoidance of predisposing factors to migraine-like caffeine
- Post-administration assessment for side effects including numbness, tingling sensation, feeling of pressure and burning sensation.
- Assess the patient’s coping mechanism with migraine
Potential side effects/Adverse effects/Toxicities
The patient should be taught how to accurately identify and describe the side effects of the drugs and the necessary precautions.
The following side effects should be reported immediately:
- Pressure or chest tightness
- Shortness of breath
- Rebound headache
- Jaw pain
- Seizures or any other neurological observations
Special considerations
The patient should be informed on the possibility of the binding of the drug to melanin, which might result in toxicity to tissues rich in melanin, thus prolonged use should be avoided.
Pregnant mothers with migraine have an increased risk of developing preeclampsia with the use of sumatriptan. Additionally, lactating mothers are advised to delay lactation for 12 hours after sumatriptan therapy. The patient is also advised to avoid foods that contain tyramine to prevent a hypertensive crisis that may develop with sumatriptan. Additional care should be taken to avoid driving or operating machinery when incidences of dizziness occur in the patient. Emergent symptoms that suggest MI or stroke should be known to the patient to ensure timely seeking of medical intervention.