Antiemetics depressants

The antiemetics and antivertigo drug may have additive effects when used with alcohol and other CNS depressants such as sedatives, hypnotics, antianxiety drugp, opiates, and antidepressants. There may be additive anticholinergic effects (see Chap. 25) when administered with drag s that have anticholinergic activity such as the antihistamines, antidepressants, pheno-thiazines, and disopyramide The antacids decrease absorption of the antiemetics. 

Preanesthetic drugs may be omitted in those 60 years or older because many of the medical disorders for which these drugsare contraindicated are seen in older individuals For example, atropine and glycopyrrolate, drugs that can be used to decrease secretions of the upper respiratory tract, are contraindicated in certain medical disorders such as prostatic hypertrophy, glaucoma, and myocardial ischemia. Other preanesthetic drugs that depress the central nervous astern (CN, such as narcotics barbiturates and antianxiety drugs with or without antiemetic properties may be contraindicated in the older individual. 

Chlorprothixene has an antipsychotic and sedative action. It has expressed antiemetic activity. It is used in various psychoses, schizophrenia, reactive and neurotic depression with prevalent anxious symptomatology, and in conditions of excitement associated with fear and stress. It may be used in small doses as a sedative agent in neurosis. Synonyms of chlorprothixene are clothixene and tarasan. 

Promethazine is not recommended in children younger than 2 years of age. Exercise caution when administering promethazine to children because of the potential for fatal respiratory depression. Limit antiemetics to prolonged vomiting of known etiology. Avoid use in children whose signs and symptoms may suggest Reye syndrome or other hepatic diseases. In children with dehydration, there is an increased susceptibility to dystonias with the use of promethazine. 

Pharmacokinetics Dimenhydrinate has a depressant action on hyperstimulated labyrinthine function. The precise mode of action is not known. The antiemetic effects are believed to be caused by the diphenhydramine, an antihistamine also used as an antiemetic agent. 

Meperidine (Demerol) [C-ll] [Narcotic Analgesic] Uses Moderate/ severe pain Action Narcotic analgesic Dose Adults. 25-50 mg IV, 50-100 mg IM Peds. 1 mg/kg IV/IM (onset w/in 5 min IV and 10 min IM duration about 2 h) Caution [C, ] Contra Convulsive disorders and acute abdomen Disp Prefilled 1 mL syringes 25, 50, 75, 100 mg/mL various amps and vials oral syrup and tabs SE N/V (may be severe), dizziness, weakness, sedation, miosis, resp d ession, xerostomia (dry mouth) Interactions t CNS depression W/ opiates, sedatives/ hypnotics TCNS stimulation W/amphetamines t risk of tox W7 phenytoin EMS Pt should be receiving O2 prior to administration have resuscitation equipment and naloxone available naloxone can be used as an antidote to reverse resp depression aspirate prior to IM administration inadv tent IV admin of IM doses may cause tach and syncope mix w/ NS to make a 10 mg/mL soln and inj very slowly N/V may be sev e may premedicate w/ an antiemetic... 

Mechanism of Action A phenothiazine that acts as an antihistamine, antiemetic, and CNS-antipsychotiC typical hypnotic. As an antihistamine, inhibits histamine at histamine receptor sites. As an antiemetic, diminishes vestibular stimulation, depresses labyrinthine function, and acts on the chemoreceptor trigger zone. As a sedative-hypnotic, produces CNS depression by decreasing stimulation to the brainstem reticular formation. Therapeutic Effect Prevents allergic responses mediated by histamine, such as rhinitis, urticaria, and pruritus. Prevents and relieves nausea and vomiting. Pharmacokinetics ... 

Promethazine (50 mg IM), an antihistaminic with sedative, antiemetic and anticholinergic properties is generally used in children as it causes little respiratory depression. 

Action on CTZ Chlorpromazine depresses the chemoreceptor trigger zone (CTZ) and acts as a powerful antiemetic agent. 

Dronabinol (Marinof) [C-ll] [Anriemeric, Appetite Stimulant/ Antivertigo] Uses N/V associated w/ CA chemo appetite stimulation Action Antiemetic 4- V center in the medulla Dose Adults Peds. Antiemetic 5-15 mg/m2/dose q4-6h PRN Adults. Appetite stimulant 2.5 mg PO before lunch dinner max 20 mg/d Caution [C, ] Contra Hx schizophrenia, sesame oil hypersensitivity Disp Caps SE Drowsiness, dizziness, anxiety, mood change, hallucinations, depersonalization, orthostatic 4- BP, tach Interactions T Effects W/ anticholinergics, CNS depressants, EtOH 4- effects of theophylline EMS Use caution w/ sympathomimetics, can T hypertension and tach use caution w/ anticholinergics and antihistamines, can T tach concurrent EtOH use can T CNS depression this is a principal psychoactive substance present in marijuana OD May cause extreme psychiatric effects (anxiety, mood changes and depersonalization) keep pt in a quiet environment and provide reassurance activated charcoal may be effective... 

Tranquilizer, sedation, antiemetic Dose Adults. N Initial max 2.5 mg IV/EM, may repeat 1.25 mg based on response Premed 2.5-10 mg IV, 30-60 min preop Peds. Premed 0.1-0.15 mg/kg/dose Caution [C, ] Contra Component sensitivity Disp Inj SE Drowsiness, i BP, occasional tach extrapyramidal Rxns, T QT interval, arrhythmias Interactions T Effects W/ CNS depressants, fentanyl, EtOH T hypotension W/ antihypertensives, nitrates EMS Monitor ECG, may T QT interval epi may cause paradoxical hypotension, do not use fentanyl may cause HTN, do not use if possible use caution w/ analgesics and opioids may T CNS depression monitor for S/Sxs of extrapyramidal Rxns which can be treated w/ Benadryl concurrent EtOH use can T CNS depression OD May cause T of nl SEs symptomatic and supportive... 

Stool softeners and cathartics can be used in children, as in adults, to relieve symptoms of constipation. Nausea and vomiting generally diminish as opioid therapy is continued, but antihistamines with antiemetic effects, such as hydroxyzine or promethazine, may be helpful as adjuvants to diminish impleasant G1 symptoms. Reducing the opioid dose to minimal analgesic levels may help to limit sedation or drowsiness. Mild respiratory depression, an uncommon side effect in children, may require only that the opioid dose be reduced. 

---