Clinical pharmacology and therapeutics
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Clin. Pharmacol. Ther. · Oct 1988
Hydromorphone levels and pain control in patients with severe chronic pain.
To better understand the use of narcotic analgesics, the hydromorphone concentration was measured in serum samples from 43 patients with chronic severe pain who were receiving this drug. At the time of blood sampling, pain intensity, mood, and cognitive performance were assessed. There was large individual variation in the dose-drug level relationship. ⋯ Poor mood correlated with high pain intensity and low drug level. Impaired cognitive performance was not related to drug level. Knowing that there is a low concentration of narcotic in the blood of a patient with chronic severe pain who is receiving high drug doses and who shows lack of both efficacy and side effects may reassure health care professionals that further narcotic dosage escalation is appropriate.
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Clin. Pharmacol. Ther. · Oct 1988
Prediction of efficacy and tolerance of oral mexiletine by intravenous lidocaine application.
In a controlled crossover trial, 15 patients with frequent ventricular arrhythmias were treated with lidocaine to predict efficacy and safety of oral mexiletine. After an initial control period, patients received intravenous lidocaine (bolus infusion of 200 mg/20 min followed by 3.6 gm/24 hr and for 7 days oral mexiletine (200 mg four times a day). Efficacy was controlled by 24-hour Holter monitoring (responders = suppression of single premature ventricular beats [PVB] greater than 84% and of complex PVB greater than 90%). ⋯ After mexiletine, five of 15 patients (33%) were responders (mean PVB reduction: 81%); efficacy was closely related to the plasma concentration. When efficacy of both agents was compared, lidocaine infusion had a positive predictive value of only 50%; however, the negative predictive value was 100%. Thus in nonresponders to lidocaine, mexiletine is very likely to fail in the suppression of ventricular ectopy.