Skip to main content

Seldane Side Effects

Generic name: terfenadine

Note: This document contains side effect information about terfenadine. Some dosage forms listed on this page may not apply to the brand name Seldane.

Applies to terfenadine: oral tablet.


Terfenadine use may cause prolongation of the QT interval. Most cardiovascular events related to terfenadine (the active ingredient contained in Seldane) occur in patients taking more than the recommended dose of 60 mg twice a day, in patients with higher-than-normal terfenadine serum concentrations, and in patients who are at risk for cardiac events. Patients with liver disease are also at risk of cardiovascular toxicity due to potential accumulation of the drug. Other predisposing factors for cardiovascular toxicity include congenital forms of QT interval prolongation, coronary artery disease, and electrolyte disorders including hypokalemia and hypomagnesemia. Although rare, arrhythmias have been reported in patients on recommended doses without apparent risk factors.[Ref]

Cardiovascular toxicity has been associated with the use of terfenadine. Reported effects include dizziness, syncopal episodes, palpitations, ventricular arrhythmias (including torsades de pointes), cardiac arrest, and cardiac death.[Ref]

Nervous system

Headaches have been reported in approximately 6% of treated patients. Terfenadine (the active ingredient contained in Seldane) has not been demonstrated to cause significant drowsiness, sedation, or impaired psychomotor skills.[Ref]


Gastrointestinal effects of terfenadine (the active ingredient contained in Seldane) are rare and include nausea and dry mouth.[Ref]


A study of the effects of terfenadine (the active ingredient contained in Seldane) on the urination of eight healthy male volunteers and 11 males with benign prostatic hypertrophy was not able to confirm a consistent effect on voiding characteristics.[Ref]

Urinary retention has been reported rarely.[Ref]


Acute hepatitis, cholestatic hepatitis, and jaundice have been reported rarely in patients taking terfenadine (the active ingredient contained in Seldane) Hepatic dysfunction has been reversible upon discontinuation of the drug.[Ref]

More about Seldane (terfenadine)

Patient resources

Related treatment guides


1. Kessler DA, Scheman C, Nightingale SL, et al. "New boxed warnings added for seldane, hismanal." FDA Med Bull 22 (1992): 2-3

2. Kemp JP "Antihistamines--is there anything safe to prescribe?" Ann Allergy 69 (1992): 276-80

3. Woosley RL, Chen Y, Freiman JP, Gillis RA "Mechanism of the cardiotoxic actions of terfenadine." JAMA 269 (1993): 1532-6

4. "Safety of terfenadine and astemizole." Med Lett Drugs Ther 34 (1992): 9-10

5. Smith SJ "Cardiovascular toxicity of antihistamines." Otolaryngol Head Neck Surg 111 Suppl (1994): 348-54

6. Salata JJ, Jurkiewicz NK, Wallace AA, Stupienski RF, Guinosso PJ, Lynch JJ "Cardiac electrophysiological actions of the histamine h-1-receptor antagonists astemizole and terfenadine compared with chlorpheniramine and pyrilamine." Circ Res 76 (1995): 110-9

7. Berul CI, Morad M "Regulation of potassium channels by nonsedating antihistamines." Circulation 91 (1995): 2220-5

8. Desager JP, Horsmans Y "Pharmacokinetic pharmacodynamic relationships of h-1-antihistamines." Clin Pharmacokinet 28 (1995): 419-32

9. Woosley RL "Cardiac actions of antihistamines." Annu Rev Pharmacol Toxicol 36 (1996): 233-52

10. June RA, Nasr I "Torsades de pointes with terfenadine ingestion." Am J Emerg Med 15 (1997): 542-3

11. Carter CA, Wojciechowski NJ, Hayes JM, Skoutakis VA, Rickman LA "Terfenadine, a nonsedating antihistamine." Drug Intell Clin Pharm 19 (1985): 812-7

12. Connell JT "Pharmacology and clinical efficacy of terfenadine, a new H1-receptor antagonist." Pharmacotherapy 5 (1985): 201-8

13. Moser L, Huther KJ, Koch-Weser J, Lundt PV "Effects of terfenadine and diphenhydramine alone or in combination with diazepam or alcohol on psychomotor performance and subjective feelings." Eur J Clin Pharmacol 14 (1978): 417-23

14. Berkowitz RB, Tinkelman DG "Evaluation of oral terfenadine for treatment of the common cold." Ann Allergy 67 (1991): 593-7

15. Lockey RF, Findley S, Mitchell DQ, Woehler T, Lieberman P, Nicodemus CF "Effects of cetirizine versus terfenadine in seasonal allergic rhinitis." Ann Allergy 70 (1993): 311-5

16. Soto J, Sacristan JA, Alsar MJ, Sainz C "Terfenadine-induced tremor ." Ann Neurol 33 (1993): 226

17. Ramaekers JG, Ohanlon JF "Acrivastine, terfenadine and diphenhydramine effects on driving performance as a function of dose and time after dosing." Eur J Clin Pharmacol 47 (1994): 261-6

18. Simons FER, Fraser TG, Reggin JD, Simons KJ "Comparison of the central nervous system effects produced by six h-1-receptor antagonists." Clin Exp Allergy 26 (1996): 1092-7

19. Adelsberg BR "Sedation and performance issues in the treatment of allergic conditions." Arch Intern Med 157 (1997): 494-500

20. Juniper EF, White J, Dolovich J "Efficacy of continuous treatment with astemizole (Hismanal) and terfenadine (Seldane) in ragweed pollen-induced rhinoconjunctivitis." J Allergy Clin Immunol 82 (1988): 670-5

21. Spaulding HS, Sutherland RS, Sklarew PR, Punja MK, Thrasher JB, Vaughan TR, Donatucci CF "Effect of terfenadine on urination." Ann Allergy 72 (1994): 441-5

22. Seggev JS, Fink JN "Urinary retention as a result of administration of terfenadine." J Allergy Clin Immunol 93 (1994): 1071-2

23. Sahai A, Villeneuve JP "Terfenadine-induced cholestatic hepatitis." Lancet 348 (1996): 552-3

24. Larrey D, Palazzo L, Benhamou JP "Terfenadine and hepatitis." Ann Intern Med 103 (1985): 634

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.