Testing of analgesic effect of fluoxetine.

Fluoxetine is used in treatment of depression caused by a variety of different factors and from year to year new indications are being added, especially in conditions followed with strong bouts of pain. Additional fluoxetine based therapy that is known to help in improvement of mental state and mood stabilization can significantly increase analgesic effects. Analgesic effects of fluoxetine as well as of fluoxetine in combination with morphine were analyzed on albino mice of both genders. The sense of pain was induced by thermal stimulus by the method of hot plate. Analgesic effect was measured 30, 60, 90 and 120 minutes after a single i.p. administration of fluoxetine in following dosages: 5, 10 and 20 mg/kg. The control group was treated with 0.1 ml/10 g physiological solution. Test group injected with morphine s.c. (7 mg/kg) was used to observe the effect of fluoxetine in combination with morphine. Fluoxetine applied in 5 mg/kg dosage causes increased pain reaction 60 and 90 minutes (p=0.049 and p=0.002) (t-test) following application when compared with corresponding values of control group. When fluoxetine is applied in 10 mg/kg dosage duration of pain reaction is significantly increased after 30 (p=0.01), 60 (p=0.001) and 90 minutes (p=0.026), when compared to the control group. When fluoxetine is applied in 20 mg/kg dosage duration of pain reaction is increased 60 and 120 minutes (p<0.001) after application when compared to the control group. After application of fluoxetine (5 mg/kg) in combination with morphine, reaction time to pain is significantly extended (p<0.001) 60, 90 and 120 minutes after application when compared to the control group injected exclusively with morphine. Fluoxetine causes analgesic effect in all three applied dosages as well as it significantly increases analgesic effect when applied in 5 mg/kg dosage in combination with morphine.