In pharmacokinetic studies, mild to moderately increased haloperidol concentrations have been reported when haloperidol was given concomitantly with drugs characterized as substrates or inhibitors of CYP3A4 or CYP2D6 isoenzymes, such as itraconazole, nefazodone, buspirone, venlafaxine, alprazolam, fluvoxamine, quinidine, fluoxetine, sertraline, chlorpromazine, and promethazine.
When prolonged treatment (1 to 2 weeks) with enzyme-inducing drugs such as rifampin or carbamazepine is added to haloperidol therapy, this results in a significant reduction of haloperidol plasma levels.
In a study of 12 schizophrenic patients coadministered oral haloperidol and rifampin, plasma haloperidol levels were decreased by a mean of 70% and mean scores on the Brief Psychiatric Rating Scale were increased from baseline. In 5 other schizophrenic patients treated with oral haloperidol and rifampin, discontinuation of rifampin produced a mean -fold increase in haloperidol concentrations.
In a study in 11 schizophrenic patients co-administered haloperidol and increasing doses of carbamazepine, haloperidol plasma concentrations decreased linearly with increasing carbamazepine concentrations.
Thus, careful monitoring of clinical status is warranted when enzyme inducing drugs such as rifampin or carbamazepine are administered or discontinued in haloperidol-treated patients. During combination treatment, the haloperidol dose should be adjusted, when necessary. After discontinuation of such drugs, it may be necessary to reduce the dosage of haloperidol.
Sodium valproate, a drug known to inhibit glucuronidation, does not affect haloperidol plasma concentrations.
By adding 400mg per week of nandrolone to a testosterone cycle or a dianabol cycle , you’ll be able to increase your overall steroid dosage, without increasing the side effects. For example, a bodybuilder taking 500mg Sustanon 250 per week, who felt he needed more power in his cycle, would find himself with more side-effects if he were to just take more of the same testosterone. Since testosterone aromatizes at an increasing rate at higher doses, there would be an exponential increase in the likeliness of gynecomastia and water retention if more testosterone was added weekly. When adding nandrolone decanoate to the same testosterone cycle, you are increasing the total amounts of steroids your body is receiving every week. However, you are not adding anymore viable substrate for undesired enzymatic reactions from aromatase and 5-reductase. In simple terms, you use more steroids without more side effects.