Phenothiazines Levodopa

Dicyclomine (Bentyl) [Anrimuscarinic, GI Anrispasmodic/ Anticholinergic] Uses Functional IBS Action Smooth-muscle relaxant Dose Adults. 20 mg PO qid T to 160 mg/d max or 20 mg EM q6h, 80 mg/d - qid then T to 160 mg/d, max 2 wk Feds. Infants >6 mo 5mg/dose tid-qid Children 10 mg/dose tid-qid Caution [B, -] Contra Infants <6 mo, NAG, MyG, severe UC, BOO Disp Caps, tabs, syrup, inj SE Anticholinergic SEs may limit dose Interactions T Anticholinergic effects W/ anticholinergics, antihistamines, amantadine, MAOIs, TCAs, phenothiazides T effects OF atenolol, digoxin X effects H7 antacids X effects OF haloperidol, ketoconazole, levodopa, phenothiazines EMS Avoid procainamide usage, may T adverse effects may T effects of digoxin, monitor... 

Allopurinol, aspirin, carbamazepine, chlorpropamide, clomipramine, clozapine, colchicine, desipramine, gold salts, imipramine, levodopa, penicillamine, phenothiazines, phenytoin, propylthiouracil, and sulfonylureas... 

Chlorpromazine is an aliphatic phenothiazine antipsychotic used in schizophrenia and which may exacerbate parkinsonism. Co-careldopa is a combination of levodopa and the peripheral dopa-decarboxylase inhibitor, carbidopa. Co-careldopa, amantadine, entacapone and bromocriptine are all indicated in the management of parkinsonism. 

Drugs that may be affected by methyidopa include haloperidol, levodopa, lithium, sympathomimetics, MAOIs, anesthetics, and phenothiazines. 

Acetaminophen Amiodarone Carbamazepine Cardiac glycosides Corticosteroids Dicumarol Disopyramide Doxycycline Estrogens Haloperidol Methadone Metyrapone Mexiletine Oral contraceptives Quinidine Theophylline Valproic acid Cyclosporine Dopamine Furosemide Levodopa Levonorgestrel Mebendazole Nondepolarizing muscle relaxant Phenothiazines Sulfonylureas... 

Antiadrenergic] Uses HTN Action Centrally acting antihypCTtensive Dose Adults. 250-500 mg PO bid-tid (max 2-3 g/d) or 250 mg-1 g IV q6-8h Peds. 10 mg/kg/24 h PO in 2-3 doses (max 40 mg/kg/24 h q6-12h) or 5-10 mg/kg/dose IV q6-8h to total dose of 20 0 mg/kg/24 h X in renal insuff/elderly Caution [B (PO), C (IV), +] Contra Liver Dz MAOIs Disp Tabs, inj SE Discolors urine initial transient sedation/drowsiness frequent, edema, hemolytic anemia, hepatic disorders Interactions T Effects W/ anesthetics, diuretics, levodopa, Li, methotrimeprazine, thioxanthenes, vasodilators, verapamil T effects OF haloperidol, Li, tolbutamide effects W/amphetamines, Fe, phenothiazine, TCAs ... 

Uses Endogenous depression Action TCA T synaptic CNS levels of serotonin /or norepinephrine Dose Adults. 25 mg PO tid-qid >150 mg/d not OK Elderly. 10-25 mg hs Peds. 6-7 y 10 mg/d 8-11 y 10-20 mg/d >11 y 25-35 mg/d, 4- w/ hepatic insuff Caution [D, +/-] NAG, CV Dz Contra TCA allergy, use w/ MAOI Disp Caps, soln SE Anticholinergic (blurred vision, retention, xerostomia) Interactions T Effects W/ antihistamines, CNS depressants, cimetidine, fluoxetine, OCP, phenothiazine, quinidine, EtOH T effects OF anticoagulants T risk of HTN W/clonidine, levodopa, sympathomimetics T effects W/barbiturates, carbamazepine, rifampin EMS Concurrent use w/ MAOIs have resulted in HTN,... 

When levodopa is given without a peripheral decarboxylase inhibitor, anorexia and nausea and vomiting occur in about 80% of patients. These adverse effects can be minimized by taking the drug in divided doses, with or immediately after meals, and by increasing the total daily dose very slowly antacids taken 30-60 minutes before levodopa may also be beneficial. The vomiting has been attributed to stimulation of the chemoreceptor trigger zone located in the brain stem but outside the blood-brain barrier. Fortunately, tolerance to this emetic effect develops in many patients. Antiemetics such as phenothiazines should be avoided because they reduce the antiparkinsonism effects of levodopa and may exacerbate the disease. 

The pharmacologic basis of these disorders is unknown, and there is no satisfactory medical treatment for them. A subset of patients respond well to levodopa medication (dopa-responsive dystonia), which is therefore worthy of trial. Occasional patients with dystonia may respond to diazepam, amantadine, antimuscarinic drugs (in high dosage), carbamazepine, baclofen, haloperidol, or phenothiazines. A trial of these pharmacologic approaches is worthwhile, though often not successful. Patients with focal dystonias such as blepharospasm or torticollis often benefit from injection of botulinum toxin into the overactive muscles. The role of deep brain stimulation for the treatment of these conditions is being explored. 

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