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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pentazocine, cyclazocine, and nalorphine are narcotic antagonists that also have analgesic activity of their own. The present investigation compared the stimulus properties of these three drugs in rats. Each drug was used as a discriminative stimulus for a separate group of rats. Depression of one lever resulted in food reinforcement following the administration of drug, and the opposite lever was reinforced after saline. Each drug readily acquired control of discriminated responding. The specific narcotic antagonist, naloxone, which antagonizes many of the effects of pentazocine, cyclazocine, and nalorphine, also antagonized the discrimination of these drugs. Stimulus generalization tests to each other narcotic antagonist, d-amphetamine, morphine, and LSD, showed that each narcotic antagonist has highly specific stimulus properties. Clear generalization occurred only to pentazocine and cyclazocine in the nalorphine-saline group, but neither cyclazocine nor pentazocine generalized to nalorphine.
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PMID:Pentazocine, cyclazocine, and nalorphine as discriminative stimuli. 41 47

The effects of 2 doses of nefopam, d-amphetamine, pentazocine, and placebo were studied in healthy male sleep-deprived volunteers to determine whether the drugs improved or impaired coordination and whether they induced subjective effects. A critical tracking task was used to study hand-eye coordination. D-amphetamine, 10 mg orally, significantly improved tracking performance and made subjects feel better able to perform tasks but more anxious. It also made them feel more alert, steady, sociable, and strong. Pentazocine, 45 mg intramuscularly, caused deterioration in tracking performance and was followed by reports of depression, gloominess, dreaminess, nausea, and injection site pain. There was no significant change in tracking performance or subjective effects after both doses of nefopam and placebo.
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PMID:Effects of nefopam on visual tracking. 48 93

A 2X2 factorially designed study has been done to determine the respiratory effects of pentazocine and doxapram in terms of the minute ventilation end-expiratory PCO2 response curve. Pentazocine 30 mg intramuscularly produced marked respiratory depression. Doxapram 60 mg intramuscularly produced significant respiratory stimulation. When this dose of doxapram was given in combination with 30 mg pentazocine it produced significant reduction in the amount of respiratory depression induced by the narcotic. The statistical analysis did not show that there was anything to suggest this effect was more than additive.
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PMID:[The respiratory effect of doxapram and pentazocine and their interaction (author's transl)]. 121 84

The agonist-antagonist opioid analgesics are a heterogeneous group of drugs with moderate to strong analgesic activity comparable to that of the pure agonist opioids such as codeine and morphine but with a limited effective dose range. The group includes drugs which act as an agonist or partial agonist at one receptor and an antagonist at another (pentazocine, butorphanol, nalbuphine, dezocine) and drugs acting as a partial agonist at a single receptor (buprenorphine). These drugs can be classified as nalorphine-like or morphine-like. Meptazinol does not fit into either classification and occupies a separate category. Pentazocine, butorphanol and nalbuphine are weak mu-antagonists and kappa-partial-agonists. All three drugs are strong analgesics when given by injection: pentazocine is one-sixth to one-third as potent as morphine, nalbuphine is slightly less potent than morphine, and butorphanol is 3.5 to 7 times as potent. The duration of analgesia is similar to that of morphine (3 to 4 hours). Oral pentazocine is closer in analgesic efficacy to aspirin and paracetamol (acetaminophen) than the weak opioid analgesics such as codeine. Neither nalbuphine nor butorphanol is available as an oral formulation. At usual therapeutic doses nalbuphine and butorphanol have respiratory depressant effects equivalent to that of morphine (though the duration of such effects with butorphanol may be longer). Unlike morphine there appears to be a ceiling to both the respiratory depression and the analgesic action. All of these 3 drugs have a lower abuse potential than the pure agonist opioid analgesics such as morphine. However, all have been subject to abuse and misuse, and pentazocine (but not the others) is subject to Controlled Drug restrictions. Buprenorphine is a potent partial agonist at the mu-receptor, and by intramuscular injection is 30 times as potent as morphine. A ceiling to the analgesic effect of buprenorphine has been demonstrated in animals and it is also claimed in humans. However, there are no reliable data available to define the maximal dose of buprenorphine in humans. A practical ceiling exists for sublingual use in that the only available formulation is a 2 micrograms tablet and few patients will accept more than 3 or 4 of these in a single dose. The duration of analgesia is longer than that of morphine, at 6 to 9 hours. There have been suggestions that buprenorphine causes less respiratory depression than morphine, but viewed overall it appears that in equianalgesic doses the 2 drugs have similar respiratory depressant effects.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Opioid agonist-antagonist drugs in acute and chronic pain states. 171 41

Pentazocine and tripelennamine, which have been abused in combination by humans, were evaluated for pharmacologic interactions on autonomic, behavioral, and antinociceptive measures in chronic spinal dogs. Pentazocine (0.31-5 mg/kg, IV) produced miosis, hypothermia and antinociception which was mediated by spinal and supraspinal reflexes; these effects were antagonized by naltrexone. Tripelennamine (0.63-2.5 mg/kg, IV) elicited mydriasis, hyperthermia and antinociception; these effects were not blocked by naltrexone. Tripelennamine produced antinociception only on the supraspinally-mediated skin twitch reflex. Interactions between pentazocine and tripelennamine varied depending on the response measured. Effects of both drugs on pupils were additive. Temperature effects were infra-additive, with the hyperthermic effects of tripelennamine predominating over the pentazocine hypothermia, resulting in a complete physiologic antagonism of pentazocine hypothermia. Antinociception, measured by flexor reflex depression, represented only the effect of pentazocine, whereas skin twitch reflex antinociception reflected either infra-additive or additive properties. The coadministration of nonconvulsive doses of pentazocine and tripelennamine produced seizures indicating a potentiated adverse interaction. In summary, the patterns of the pentazocine-triplennamine interactions were complex and the effects of tripelennamine could not be attributed to opioid activity.
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PMID:Interactions between pentazocine and tripelennamine on autonomic and nociceptive measures in the dog. 278 Jul 81

The opioid agonist-antagonists are a heterogeneous group of compounds capable of providing analgesia sufficient to treat moderate to severe acute pain. Pentazocine, butorphanol and nalbuphine produce subjective effects which are quite different from those of morphine. Lack of mood elevation and occasional dysphoria may contribute to a lower level of patient acceptance, but all of these analgesics are significantly safer than the pure agonists. Doses in the therapeutic range are unlikely to produce dangerous levels of respiratory depression in most patients. Other opioid side-effects such as nausea, constipation and biliary spasm appear to be less frequent as well. The mu partial agonist buprenorphine shares many of the safety advantages of the older drugs, and its subjective effects appear more morphine-like. It is not clear whether mu partial agonists have real clinical advantages over kappa-type analgesics. All of these drugs are opioid antagonists and are able to precipitate abstinence in individuals with significant prior exposure to opiates. Neither absolute potency nor the ratio of agonist to antagonist effect are predictors of therapeutic usefulness. There is now an enormous amount of clinical experience with the agonist-antagonists. In many, but not all, clinical situations they are acceptable alternatives to the morphine-like drugs.
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PMID:The clinical usefulness of agonist-antagonist analgesics in acute pain. 289 87

Cardiohemodynamic and respiratory effects of eptazocine, a new analgesic agent, were studied and compared with those of pentazocine and butorphanol in anesthetized dogs. Eptazocine (1 mg/kg, i.v.) increased the heart rate (HR), left ventricular dP/dt (LVdP/dt) and cardiac output (CO), and scarcely affected the blood pressure (BP), left ventricular end-diastolic pressure (LVEDP), right atrial pressure, pulmonary arterial pressure (PAP) and pulmonary capillary wedge pressure. On the other hand, eptazocine (3 mg/kg, i.v.) decreased BP, LVdP/dt, CO and LVEDP and did not influence the pulmonary circulation. Pentazocine (1 mg/kg and 3 mg/kg, i.v.) increased BP, LVdP/dt and CO, while HR was not altered. Pentazocine also increased PAP. Butorphanol (0.1 mg/kg and 0.3 mg/kg, i.v.) decreased BP, HR and LVdP/dt, while other hemodynamic parameters were not changed. In spontaneously breathing anesthetized dogs, eptazocine (1 mg/kg and 3 mg/kg, i.v.) caused a decrease of respiratory minute volume. The fall in PO2 and pH, and a rise in PCO2 were simultaneously observed in blood gas analysis. These respiratory depressant effects of eptazocine were short-lasting, and they were less potent than those of pentazocine. Butorphanol scarcely affected the respiration. These results suggest that eptazocine has different cardiohemodynamic effects than other analgesics and produces mild respiratory depression.
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PMID:[Cardiohemodynamic and respiratory effects of eptazocine, a new analgesic agent, in anesthetized dogs]. 337 99

A patient with seizures, coma and respiratory depression after pentazocine overdose was treated successfully with naloxone and artificial ventilation. Pentazocine is an antagonist of the mu opioid receptors and a partial agonist of the kappa and sigma receptors. Because naloxone has less affinity for kappa and sigma receptors than for mu receptors, larger doses of naloxone are frequently required in the treatment of pentazocine overdose. Our case lends support to the view that large doses of the narcotic antagonist naloxone may be effective in pentazocine overdose.
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PMID:Seizures after pentazocine overdose. 374 88

Published clinical studies and extensive experience has shown that pentazocine, the first of the practical agonist/antagonist analgesics, is a potent analgesic with wide application in clinical medicine. It has been shown to have a spectrum of pharmacological activity which has qualitative differences from pure opiate agonists and these have important implications in clinical medicine. Pentazocine can provide analgesia as great as the opiates including morphine and meperidine, but does not have the same effect on mood. It is, therefore, less effective than the opiates in those situations where an anxiolytic effect is desired. Conversely, it produces less CNS depression in particular with regard to respiratory depression and nausea and vomiting. It also does not have the same potential for producing hypotension. The parenteral administration of pentazocine produces rapid strong analgesia which is of less duration than with morphine or meperidine. The oral administration of pentazocine is less predictable with regard to response but in appropriate patients it is capable of providing a similar degree of analgesia to that achieved with parenteral pentazocine. The dependence liability of pentazocine is substantially less than that with the opiates, and where abuse of parenteral pentazocine alone has taken place, it has usually been in medical and paramedical personnel seeking a support for inadequate personalities. Though physical and psychic dependence to parenteral pentazocine is undoubtedly possible, its incidence is extremely low with regard to the extent of the therapeutic use of pentazocine.
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PMID:Pentazocine. 388 78

The effects of bolus and infusion of ciramadol, dezocine, morphine and pentazocine were examined in anesthetized dogs. Cardiopulmonary parameters, blood PCO2, PO2 and pH and plasma histamine determinations were made. Ciramadol (2 and 8 mg/kg) did not exhibit any major activity. Dezocine produced slight respiratory depression at 2 mg/kg but no cardiopulmonary effects were observed at this dose. At 8 mg/kg there were also reductions in pulmonary compliance (Cdyn) and resistance (RL), tidal volume (VT) and a marked arterial hypotension. Morphine (2 mg/kg) elicited significant effects on all parameters examined: marked bronchoconstriction, increased arterial PCO2 and pH and corresponding decrease in PO2, slight increase in heart rate and dramatic arterial hypotension. Morphine was the only agent studied to elevate plasma histamine. Histamine (0.015 mg/kg) mimicked the cardiopulmonary actions of morphine but was virtually devoid of effect on blood gases and pH. Pentazocine (8 mg/kg) did not produce bronchoconstriction but did increase VT and reduce respiratory frequency. It produced increases in arterial PCO2 and reductions in pH and PO2. There was a slight bradycardia and hypotension within this dose. These results demonstrate that both ciramadol and dezocine possess less potential than either morphine or pentazocine for producing bronchoconstriction, respiratory depression, hypotension and histamine release.
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PMID:A comparison of the cardiorespiratory effects of ciramadol, dezocine, morphine and pentazocine in the anesthetized dog. 611 23


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