EDITOR:
Khat (Catha edulis) is a herb native to East Africa and Southern Arabia that is chewed recreationally by the people of these regions to reduce fatigue and appetite. The social habit of khat chewing is increasingly prevalent in the East African and Southern Arabian communities in Europe [Reference Kassim and Croucher1]. Khat contains the pyrrolizidine alkaloids cathinone, cathine and cathidine, which are sympathomimetic amines. The euphoric, energetic and other effects derived from chewing khat are attributed to cathinone, its major active ingredient, which has a very similar structure and pharmacologic profile as amphetamine [Reference Patel2]. The use of cathinone and amphetamine is restricted in Europe, but khat use is not. The chronic or acute use of khat is associated with adverse cardiovascular and amphetamine-like effects [Reference Al-Habori3,Reference Al-Motarreb, Briancon and Al-Jaber4]. These effects may impact negatively on anaesthesia and perioperative outcome. This is a clinical report and discussion of the perioperative course of three adult patients who chewed khat habitually.
Case 1: A 24-yr-old female of South Asian origin presented for septorhinoplasty. She had no co-morbidities, was a teetotaller, but smoked tobacco. Preoperative airway inspection on the day of surgery revealed particles and discoloration on her tongue, which she attributed to khat chewing from the previous night. Perioperative cardiorespiratory parameters were normal. Anaesthesia was induced with propofol – 200 mg and fentanyl – 100 μg; and a laryngeal mask inserted for airway management. Anaesthesia was maintained with 2% sevoflurane in 65% nitrous oxide. Surgery lasted 1 h. Recovery from anaesthesia was delayed: she woke up 1 h after discontinuation of sevoflurane. The 24-h postoperative course was uneventful.
Case 2: A 33-yr-old Caucasian male presented for eye surgery. He suffered from depression, used antidepressants, smoked tobacco and cannabis, and drank 10 units of alcohol weekly. He had previously abused amphetamine. He chewed khat habitually, with the last chewing session about 8 h before surgery. Perioperative cardiorespiratory parameters were normal. Anaesthesia was induced with propofol – 300 mg and fentanyl – 200 μg; and a laryngeal mask inserted for airway management. Anaesthesia was maintained with 3–4% sevoflurane in 65% nitrous oxide. Anaesthesia and surgery were uneventful, recovery was satisfactory and the 24 h postoperative course was uneventful.
Case 3: A 39-yr-old male of East African origin presented for knee arthroscopy. He had no co-morbidities, was a teetotaller, but smoked tobacco and chewed khat. The last khat-chewing session was the previous night. He made an informed choice of spinal anaesthesia; which was achieved with 2 mL of heavy 0.5% bupivacaine. He was not sedated, but was very sleepy perioperatively. The perioperative course was uneventful.
The sympathomimetic effects of khat are produced by cathinone, its main amphetamine-like ingredient. The cardiovascular effects of khat include coronary vasospasm, myocardial ischaemia, negative inotropy, increased myocardial oxygen demand, arrhythmias, tachycardia, vasoconstriction and hypertension [Reference Al-Habori3–Reference Al-Motarreb, Al-Kebsi, Al-Adhi and Broadley6]. These effects are especially pronounced within 4 h of chewing khat [Reference Hassan, Gunaid and Abdo-Rabbo5,Reference Al-Motarreb, Al-Kebsi, Al-Adhi and Broadley6]. None of the patients in this report had chewed khat 4 h preoperatively, hence their normal perioperative cardiovascular parameters. However, vigilant perioperative monitoring was ensured including continuous electrocardiography during postoperative recovery. The effects of chronic khat use such as arrhythmias, hypertension and ischaemic cardiomyopathy are usually present in habitual users and have implications for anaesthesia. Thus, it is important to monitor and treat any perioperative cardiovascular dysfunction. It is also beneficial to use anaesthetics with minimal sympathomimetic or cardiovascular effects.
Cathinone acts like amphetamine by releasing endogenous catecholamines from central and peripheral neurons. Chronic and intense release depletes neuronal catecholamines and the sympathetic response to cardiovascular insufficiency [Reference Fischer, Schmiesing, Guta and Brock-Utne7]. Thus, refractory hypotension may occur, and should be treated promptly. However, there is a diminished pressor response to ephedrine because of catecholamine depletion. Fortunately, the patients in this report did not have hypotension perioperatively, including the patient who had spinal anaesthesia. Chronic amphetamine use can result in significantly reduced anaesthetic requirement secondary to catecholamine depletion [Reference Fischer, Schmiesing, Guta and Brock-Utne7], and may account for the delayed recovery observed in Case 1. Chronic use may also lead to the development of tolerance, fatigue and cross-tolerance to other sympathomimetics [Reference Fischer, Schmiesing, Guta and Brock-Utne7], and this may account for the perioperative sleepiness observed in Case 3 under spinal anaesthesia. Khat chewing is associated with tobacco smoking, as seen in all the cases reported [Reference Kassim and Croucher1,Reference Al-Motarreb, Al-Kebsi, Al-Adhi and Broadley6]. Other effects of chronic khat use include hepatitis, nephropathy and neuropathy [Reference Al-Habori3,Reference Brostoff, Plymen and Birns8].
Acute khat use may present a serious perioperative challenge because of the prominent adverse cardiovascular effects, especially within 4 h of chewing khat [Reference Al-Motarreb, Briancon and Al-Jaber4,Reference Hassan, Gunaid and Abdo-Rabbo5,Reference Al-Motarreb, Al-Kebsi, Al-Adhi and Broadley6]. It may also increase anaesthetic requirement and this has been observed in acute amphetamine states [Reference Fischer, Schmiesing, Guta and Brock-Utne7]. The second case in this report chewed khat 8 h preoperatively, which may explain the requirement for relatively high doses of anaesthetics, although he was cardiostable. Other effects of acute khat use include analgesia [Reference Connor, Makonnen and Rostom9], and delayed gastrointestinal motility [Reference Heymann, Bhupulan and Zureikat10], which have important anaesthetic and perioperative implications.
Optimal perioperative care of khat users requires careful titration of cardiostable anaesthetic and comprehensive monitoring. Opioid-based general anaesthesia or regional anaesthesia would be beneficial. Patients requiring emergency or major surgery should receive direct arterial pressure measurement, for better cardiovascular monitoring. Direct-acting vasopressors, such as phenylephrine or epinephrine, should be readily available to treat hypotension or bradycardia.
In conclusion, khat chewing is an international socio-medical problem with considerable physiologic and pharmacologic implications. The medical implications of khat should be considered in the health care of patients from communities in which khat use is common.
