What Medications Should Be Avoided with Long QT Syndrome?

Patient Presentation
An 11-year-old female came to clinic with a hacking cough for the past 4 days. It was bothering her during the day and night. She had no rhinorrhea, fever, nausea, vomiting or shortness of breath. Overall she just didn’t feel well but was attending school and doing her sports activities. She had multiple family members with upper respiratory tract infection symptoms over the past 2 weeks. Her father had been diagnosed with mycoplasma pneumonia 2 days ago after he had had similar symptoms and a chest x-ray that was compatible with the diagnosis. She was fully immunized including a TdaP and influenza vaccine given 4 months previously. Pertussis was circulating in the community, but not influenza. The past and family medical history showed a history of long QT syndrome that was diagnosed after the paternal grandfather had a syncopal incident. Her father and a sibling also had long QT syndrome. She had not had any problems including when taking various antibiotics and antihistamines in the past. She had been diagnosed based on electrocardiogram and genetic testing. She had no history of asthma or other lung disease. The review of systems was otherwise normal.

The pertinent physical exam revealed a tired appearing female with a respiratory rate of 18, normal heart rate and blood pressure. She was afebrile and had normal growth parameters. HEENT was normal. Lung examination had mild end-expiratory wheezing at the base and mid-right lung field. The rest of her examination was normal. The diagnosis of probable mycoplasma pneumonia was made but as she had not had wheezing before a chest x-ray was obtained that showed changes in the posterior basilar segment of the right lower lobe. This confirmed the diagnosis. Because of the history of long QT syndrome the patient was started on doxycycline. Medication for symptoms such as a small amount of codeine to help with sleeping was not encouraged because of the long QT syndrome. The family and patient understood this and said they had been through this before. They would use a humidifier and make sure that she was drinking well. The patient’s clinical course at one week found her to be still coughing, but not as forcefully as before and she was feeling better.

Case Image
Figure 113 – PA and lateral views of the chest demonstrate a faint infiltrate in the posterior basilar segment of the right lower lobe, best seen on the PA view, consistent with bacterial or mycoplasma pneumonia.

Mycoplasma pneumoniae is a frequent cause of pharyngitis, pneumonia and acute bronchitis, but acute otitis media is uncommon. Symptoms are usually self-limited and variable and include cough (non-productive usually but later can be productive), fever, fatigue and occasionally headache. Coryza is rare. Cough can continue for 3 to 4 weeks and can be accompanied by wheezing. Radiographic changes include diffuse infiltrates or focal abnormalities but are variable.

Long QT syndrome (LQTS) is a group of disorders that have a prolonged QT interval and a polymorphic ventricular tachycardia. Torsade de pointes (“twisting of the points”) is a particular type of polymorphic ventricular tachycardia that can be associated with LQTS. LQTS can be congenital or acquired. It is increasingly being recognized and may be as common as 1:2500.

Congenital LQTS has many different types. It is associated with chromosomal changes which cause myocardial ion channel problems which interferes with normal cardiac polarization-repolarization leading to arrhythmias. LQT1 accounts for 30-35% of LQTS. LQT2 accounts for 25-40%. LQT3 accounts for 5-10% of patients, and the others account for the remaining percentages. Phenotypically there are two main clinical phenotypes. Romano-Ward syndrome is an autosomal dominant trait that has LQTS without sensorineural deafness. Jervell and Land-Nielsen syndrome is an autosomal recessive trait that has LQTS with bilateral sensorineural deafness. Interestingly, some studies have reported up to 4% of patients who have sensorineural hearing loss to have Jervell and Lange-Nielsen syndrome, but a 2013 study of patients with sensorineural hearing problems identified in statewide newborn hearing screening program found no cases of Jervell and Lange-Nielsen syndrome.

Acquired LQTS usually occurs because of medications but also through various metabolic disorders (particularly hypokalemia or hypomagnesemia), bradyarrhythmias, and other miscellaneous causes.

LQTS manifestations include syncope, ventricular tachyarrhythmias, torsade de pointes and also cardiac arrest or unexplained sudden death. Patients may also be identified through family history or incidental ECG findings. LTQTS subtypes influence the arrhythmia risk and also the choice of treatment including no specific treatment for some patients. Maintenance of normal electrolytes, avoidance of extreme exertion and many different medications are necessary for many patients. The mainstay of treatment for many patients is beta-blockers. Additionally implantable cardiac defibrillators or permanent pacemakers are also used. Surgical denervation of the heart through ligation of the stellate ganglion is also sometimes used.

Episodes can be precipitated by emotion, stress, sleep, sudden noises, and exertion.

Learning Point
Medication choice always requires careful consideration. Patients with LQTS need particular attention as many medications can interfere with cardiac polarization/repolarization.

There are several categories of common medications that should be avoided in patients with LQTS including:

  • Antibiotics – macrolides, fluoroquinolones, trimethoprim-sulfa
  • Antifungals – some azole antifungals
  • Antihistamines – terfenadine and astemizole have been withdrawn from the market because of this risk
  • Antiemetics and promotility agents – ondansteron, phenergen, cisapride
  • Cough/cold medications – pseudoephedrine
  • Stimulant medications – methylphenidate
  • Pain and sedatives – chloral hydrate, oxycodone, methadone
  • Anti-depressants – including tricyclic antidepressants and some selective serotonin reuptake inhibitors including citalopram, fluoxetine.
  • Other groups include antiarrhythmic drugs, antineoplastic drugs, diuretics (because of electrolyte abnormalities), other psychotropic medications and even some herbs.

The list of medications to avoid changes with new medication availability, and new knowledge about the medications and LQTS itself. CredibleMeds® sponsored by the non-profit organization Azcert.org provides one list of medications that should be avoided with LQTS. It is available here. Consultation with the patient’s cardiologist and pharmacist should also be considered when treating patients. Real-life conundrums occur when patients with LQTS have competing problems and risks that also must be addressed such as the need for sedation or patients with asthma who need beta-agonists. Team management with appropriate personnel in concert with cardiologists and prior planning for such problems can assist other care providers when these situations arise.

Questions for Further Discussion
1. What tests are available for mycoplasma?
2. What is the difference between an implantable pacemaker and an implantable defibrillator?

Related Cases

    Symptom/Presentation: Cough

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Arrhythmia and Pneumonia.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Mikesell CE, Atkinson DE, Rachman BR. Prolonged QT syndrome and sedation: a case report and a review of the literature. Pediatr Emerg Care. 2011 Feb;27(2):129-31.

Collins S, Widger J, Davis A, Massie J. Management of asthma in children with long QT syndrome. Paediatr Respir Rev. 2012 Jun;13(2):100-5.

Mycoplasma pneumoniae and Other Mycoplasma Species Infections. Report of the Committee on Infectious Diseases. Pickering LK, ed., 29th ed. American Academy of Pediatrics, Elk Grove Village, IL, 2012.

Chang RK, Lan YT, Silka MJ, Morrow H, Kwong A, Smith-Lang J, Wallerstein R, Lin HJ. Genetic variants for long QT syndrome among infants and children from a statewide newborn hearing screening program cohort. J Pediatr. 2014 Mar;164(3):590-5.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    7. All medical and invasive procedures considered essential for the area of practice are competently performed.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Interpersonal and Communication Skills
    17. A therapeutic and ethically sound relationship with patients is created and sustained.


    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital