There have been case reports of bradycardia and association with administration of high-dose corticosteroids or clindamycin or immunoglobulin, but the data are incomplete. Clindamycin administration is the treatment of severe infections caused by anaerobic bacteria since it is very effective against gram-negative and -positive organisms, cocci, and anaerobic bacteria like Chlamydia trachomatis (9). Clindamycin can cause gastrointestinal discomfort, nausea, vomiting, diarrhea, hepatotoxicity, maculopapular rash, anorexia, flatulence, drug fever, and Stevens-Johnson syndrome, some of its common side effects (10, 11). A higher liver transaminase level, monoarthritis, hematopoietic effects such as neutropenia, leukopenia, agranu-locytosis, and thrombocytopenic purpura, cardio-pulmonary arrest, hypotension, and excessive bleeding are less common adverse events (9-14). Sinus bradycardia is an adverse effect of clindamycin which is reported less frequently. In their case report, Sedigheh Ghasemian et al. reported that sinus bradycardia could be a side effect of Clindamycin in the treatment of septic abortion (15). In this case, symptomatic bradycardia occurred four hours after the start of clindamycin and improved three days after discontinuation. The administration of IVIG seems to be promising in clinical practice. While IVIG is usually tolerated well, there have been several reported adverse reactions, most of which are transient and mild, including flushing, headache, malaise, fever, chills, fatigue, and lethargy. However, some rare side effects may present as severe, including renal impairment, thrombosis, arrhythmia, aseptic meningitis, and hemolytic anemia (16). In therapy with IVIg, F. D'Andrea et al. reported a case about sinus bradycardia in a patient with bacterial meningitis (17). Steven Douedi et al. likewise have reported a case that IVIG infusion can result in severe bradycardia, even in patients with no previous cardiac history. These patients are asymptomatic and don't require any treatment (18). In this case, too, the patient showed symptomatic bradycardia after receiving one dose of IVIg.
In practice, high-dose intravenous corticosteroid therapy, also known as pulse steroid therapy (PST), is frequently used. Hyperglycemia, gastrointestinal intolerance, minor infections, and psychiatric symptoms are the most common adverse effects of high-dose PST (19). The following are examples of minor adverse effects that can occur: transient facial flushing, a short disturbance of taste, distal paresthesia, insomnia, and mild weight gain (8). In general, high-dose corticosteroid therapy is associated with cardiac arrhythmias (atrial fibrillation/flutter, ventricular tachycardia, and sinus bradycardia) in 1% to 82% of patients (19-20). One of the rare adverse effects of PST is bradycardia which is usually asymptomatic. A case report by Alessandro Sodero et al. has described a 48-year-old woman with inflammatory myelitis who developed severe and symptomatic sinus bradycardia after five days of PST (21). Amartya Kundu described a woman during her treatment for multiple sclerosis who showed acute sinus bradycardia after receiving the pulse dose of steroids (22). In a study by Tvede et al., five patients who were being treated for rheumatoid arthritis received high-dose intravenous methylpre-dnisolone. All five of them experienced sinus bradycardia, although only one patient was symptomatic with chest tightness. The sinus brady-cardia was self-limiting in all of them, but for the heart rate, it took as long as seven days to return to normal (23). The temporal association between the IVIg and clindamycin and development of bradycardia and also in our patient according to continued use of corticosteroids, suggest the clindamycin and IVIg maybe this etiology.
 

In our limited experience, clindamycin can result in severe bradycardia, even in patients with no previous cardiac history, especially when combined with IVIg and corticosteroids because these medications may have potentially induced severe bradycardia. It is suggested that monitoring of general conditions and vital signs during treatment is recommended for the possible causal link between clindamycin or IVIgs and bradycardia, especially in the case of simultaneous administration of corticosteroids. Further studies are needed to verify this relation.

 

The authors thank all the staff members of the obstetrics and gynecology department of Shahid Motahhari Hospital, Urmia, for their help and suggestions.

 

The authors declared no conflict of interest.

 

Written informed consent was obtained from the patient.