CASE REPORT A case of probable labetalol induced hyperkalaemia in pre-eclampsia Binny Thomas • P. V. Abdul Rouf • Wessam El Kassem • Moza Al Hail • Derek Stewart • Asma Tharannum • Afif Ahmed • Muna Al Saadi Received: 26 April 2014 / Accepted: 25 September 2014 / Published online: 5 November 2014 Ó Koninklijke Nederlandse Maatschappij ter bevordering der Pharmacie 2014 Abstract Case description Hyperkalemia can cause altered cardiac electrical conduction resulting in death. We describe a case of a 23-year old pregnant patient who presented with severe epigastric pain and vomiting. She was severely pre- eclamptic and received initial treatment with intravenous labetalol and decision was taken to deli- ver. She quickly became hyperkalaemic (serum potassium level 6.4 mmol/L) and labetalol was discontinued and intravenous hydralazine commenced. Post-surgery, her potassium levels were normal but due to rapidly rising blood pressure labetalol was recommenced, resulting in elevated potassium levels. Labetolol was discontinued, hydralazine prescribed, and potassium levels normalised. The adverse reaction was classified as ‘probably’ due to labetolol using the Naranjo Adverse Drug Reaction scale. Conclusion This is the first reported case of labetolol induced hyperkalaemia in pregnancy, with life threatening consequences and hence all health professionals should be alert to this potential effect. Keywords Hyperkalemia Á Labetolol Á Pre-eclampsia Á Pregnancy Impacts on practice • Health professionals treating pre-eclampsia should be alert to the potential of labetolol induced hyperkalaemia. • Serum potassium levels should be carefully monitored if prescribing intravenous labetolol. Introduction Pregnancy related hypertension is a leading cause of peripartum morbidity and mortality. Pre-eclampsia and eclampsia are potentially life threatening conditions which require urgent antihypertensive management, with intravenous labetalol commonly prescribed either first or second line [1, 2]. Hyperkalaemia occurs when serum potassium concen- tration exceeds 5.1 mmol/L. In hospitalised patients, the incidence of hyperkalaemia has been reported at between 1.3 and 10 % of patients. Consequences of hyperkalaemia include neuromuscular effects and, more seriously, altered cardiac electrical conduction which can result in death [3]. Many drugs may contribute to hyperkalaemia, most notably potassium sparing diuretics, angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists. As catecholamines stimulate the intracellular uptake of potassium, beta adrenoceptor antagonists can also theo- retically precipitate hyperkalaemia. However, this effect is relatively uncommon and largely reported in patients with renal insufficiency [4, 5]. Cases of labetalol induced hyperkalaemia are very rare; a search of the United Kingdom (UK) Medicines and Healthcare products Regulator Agency (MHRA) database failed to identify any reports [6]. Only one case of intra- venous labetalol induced hyperkalaemia, leading to patient death, was identified from the Canadian adverse drug reaction monitoring database [7]. We report a potentially life threatening case of labetalol induced hyperkalaemia in a severely hypertensive pregnant B. Thomas (&) Á P. V. Abdul Rouf Á W. E. Kassem Á M. A. Hail Á D. Stewart Á A. Tharannum Á A. Ahmed Á M. A. Saadi Hamad Medical Corporation, Doha, Qatar e-mail: binnyinhmc@gmail.com 123 Int J Clin Pharm (2014) 36:1130–1133 DOI 10.1007/s11096-014-0021-z