Posted by: Thixia | June 26, 2008

Dizziness, Vertigo, and Imbalance Section 6 of 8

MEDICATION

 

Drug Category: Antihistamine

These drugs prevent the histamine response in sensory nerve endings and blood vessels and are effective in treating vertigo.

Drug Name

Meclizine (Antivert)

Description

Decreases excitability of inner-ear labyrinth and blocks conduction in inner-ear vestibular-cerebellar pathways.  Effects are associated with therapeutic effects in relief of nausea and vomiting.  Most effective if used prn for 2-3 d with episodes of true vertigo.

Adult Dose

25 mg PO q4-6h

Pediatric Dose

<12 years: Not established

>12 years: Administer as in adults

Contraindications

Documented hypersensitivity

Interactions

May increase toxicity of CNS depressants, neuroleptics, and anticholinergics

Pregnancy

B – Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Caution in angle-closure glaucoma, prostatic hypertrophy, pyloric or duodenal obstruction, and bladder neck obstruction

 

Drug Name

Dimenhydrinate (Dramamine)

Description

A 1:1 salt of 8-chlorotheophylline and diphenhydramine believed to be particularly useful in treatment of vertigo.  Diminishes vestibular stimulation and depresses labyrinthine function by means of central anticholinergic activity.

Adult Dose

50 mg PO/IM q4-6h or 100-mg supp q8h

Pediatric Dose

2-6 years: Up to 12.5-25 mg PO/IM q6-8h; not to exceed 75 mg/d

6-12 years: 25-50 mg PO q6-8h; not to exceed 150 mg/d

>12 years: Administer as in adults

Contraindications

Documented hypersensitivity; administration to neonates (IV products may contain benzyl alcohol, which has been associated with fatal gasping syndrome in premature infants and low-birth-weight infants)

Interactions

Alcohol or other CNS depressants may have additive effect; caution with concurrent antibiotics that may cause ototoxicity; may mask ototoxic symptoms caused by certain antibiotics (irreversible damage may result)

Pregnancy

B – Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Do not treat severe emesis with antiemetic drugs alone; may contain either sulfites or tartrazine, which may cause allergic-type reactions in susceptible persons; may impede diagnosis of conditions such as brain tumors, intestinal obstruction, and appendicitis; may obscure signs of toxicity from overdosage of other drugs

 

Drug Category: Anticholinergic agent

These agents are thought to work centrally by suppressing conduction in the vestibular-cerebellar pathways.

Drug Name

Scopolamine (Isopto)

Description

Blocks action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands, and CNS.  Antagonizes histamine and serotonin action.  Transdermal may be most effective agent for motion sickness.  Use in treatment of vestibular neuronitis limited by slow onset of action.  Severe adverse effects preclude use in elderly.  Robinul more effective and has fewer adverse effects, especially in elderly patients.

Adult Dose

0.6 mg PO q4-6h or 0.5 mg TD q3d

Pediatric Dose

6 mcg/kg/dose IV/IM/SC; not to exceed 0.3 mg/dose; or 0.2 mg/m2 repeated q6-8h

Contraindications

Documented hypersensitivity; primary glaucoma (including initial stages); pyloric obstruction; toxic megacolon; hepatic disease; paralytic ileus; severe ulcerative colitis; renal disease; obstructive uropathy; myasthenia gravis

Interactions

Antipsychotic effectiveness of phenothiazines may be decreased with coadministration; concurrent therapy may increase anticholinergic adverse effects (adjust phenothiazine dosages prn); coadministration with tricyclic antidepressants (TCAs) may increase anticholinergic adverse effects (eg, dry mouth, constipation, urinary retention) due to additive effect (TCAs with decreased anticholinergic activity may be beneficial)

Pregnancy

C – Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in elderly patients because of increased incidence of glaucoma; large doses may suppress intestinal motility and precipitate or aggravate toxic megacolon; anticholinergics may aggravate hiatal hernia associated with reflux esophagitis; patients with prostatism can have dysuria and may require catheterization; use cautiously in patients with asthma or allergies; reduction in bronchial secretions can lead to inspissation and formation of bronchial plugs

 

Drug Name

Glycopyrrolate (Robinul)

Description

Blocks action of acetylcholine at parasympathetic sites.

Adult Dose

1-2 mg PO bid/tid

Pediatric Dose

40-100 mcg/kg per dose PO tid/qid

Contraindications

Documented hypersensitivity; narrow-angle glaucoma, tachycardia, ulcerative colitis, paralytic ileus, or acute hemorrhage

Interactions

Levodopa decreases effects of glycopyrrolate; both amantadine and cyclopropane increase glycopyrrolate toxicity

Pregnancy

C – Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

May increase megacolon, hyperthyroidism, congestive heart failure (CHF), coronary artery disease (CAD), hiatal hernia, and benign prostatic hyperplasia (BPH); not recommended for children <12 y or patients with Down syndrome

 

Drug Category: Benzodiazepine

By binding to specific receptor sites, these agents appear to potentiate effects of gamma-aminobutyric acid (GABA) and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters.  These effects may prevent vertigo and emesis.

Drug Name

Diazepam (Valium)

Description

Effective in treating vertigo.  Depresses all levels of CNS, including limbic and reticular formation, possibly by increasing activity of GABA, major inhibitory neurotransmitter.  Individualize dosage and cautiously increase to avoid adverse effects.  Effective for acute episodes.  Discontinue as quickly as possible to maximize cerebellar vestibular compensation process.

Adult Dose

5-10 mg PO/IV/IM q4-6h

Pediatric Dose

<6 months: Not recommended

>6 months:

0.05-0.3 mg/kg/dose IV/IM over 2-3 min, repeat in 2-4 h prn

0.12-0.8 mg/kg/d PO divided q6-8h; not to exceed 10 mg/dose

Contraindications

Documented hypersensitivity

Interactions

Increases toxicity of benzodiazepines in CNS with coadministration of phenothiazines, barbiturates, alcohols, and monoamine oxidase inhibitor (MAOIs)

Pregnancy

D – Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)

 

Drug Category: Phenothiazine

These drugs are effective in treating emesis, possibly because of their effects in the dopaminergic mesolimbic system.

Drug Name

Promethazine (Phenergan)

Description

Antidopaminergic effective in treatment of emesis.  Blocks postsynaptic mesolimbic dopaminergic receptors in brain and reduces stimuli to brainstem reticular system.  Robinul safer and has fewer adverse effects.  Well tolerated in elderly patients and does not have potential for extrapyramidal syndrome.

Adult Dose

25 or 50 mg PO/IM/PR q4-6h

Pediatric Dose

<2 years: Contraindicated

>2 years: 0.25-1 mg/kg PO/IV/IM/PR 4-6 times/d prn

Contraindications

Documented hypersensitivity; children younger than 2 y (incidences of death due to respiratory depression)

Interactions

May have additive effects when used concurrently with other CNS depressants or anticonvulsants; coadministration with epinephrine may cause hypotension

Pregnancy

C – Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Can be associated with CNS depression, dry mouth, extrapyramidal symptoms, hypertension, and skin rash; caution in cardiovascular disease, impaired liver function, seizures, sleep apnea, and asthma

 

Drug Name

Prochlorperazine (Compazine)

Description

Antidopaminergic drug that blocks postsynaptic mesolimbic dopamine receptors.  Has anticholinergic effect and can depress reticular activating system (possibly responsible for relieving nausea and vomiting).

Adult Dose

5-10 mg PO/IM q6h

25-mg supp PR q12h

Pediatric Dose

2.5 mg PO/PR q8h or 5 mg PO/PR q12h prn; not to exceed 15 mg/d

0.1-0.15 mg/kg/dose IM; change to PO when possible

Contraindications

Documented hypersensitivity; bone marrow suppression; narrow-angle glaucoma; severe liver or cardiac disease

Interactions

Coadministration with other CNS depressants or anticonvulsants may cause additive effects; administration with epinephrine may cause hypotension

Pregnancy

D – Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Drug-induced Parkinson syndrome or pseudoparkinsonism frequent; akathisia most common extrapyramidal reaction in elderly; lowers seizure threshold; caution in history of seizures

 

Drug Category: Monoaminergic

These agents may be used to treat vertigo, possibly by modulating the sympathetic system.

Drug Name

Ephedrine (Pretz-D)

Description

Stimulates release of epinephrine stores, producing alpha- and beta-adrenergic receptors.

Adult Dose

5-10 mg PO/IM q6h

25-mg supp PR q12h

Pediatric Dose

<2 years: Not recommended

2-5 years: 3 mg PO q6-8h

>5 years: 6.25 mg PO q6-8h

Contraindications

Documented hypersensitivity; angle-closure glaucoma; cardiac arrhythmias

Interactions

Theophylline, atropine, or MAOIs may increase toxicity; alpha- and beta-blockers decrease vasopressor effects of ephedrine; cardiac glycosides and general anesthetics increase cardiac stimulation of ephedrine

Pregnancy

B – Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Adverse effects (eg, excitation, tremulousness, insomnia, nervousness, palpitation, tachycardia, other symptoms associated with sympathetic activation); bladder sphincter spasm (may cause a transient acute urinary retention); caution in elderly and in patients with diabetes mellitus, hyperthyroidism, hypertension, cardiovascular disease, prostatic hypertrophy, or cerebrovascular insufficiency

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Responses

  1. You have beautiful blog. thanks for the myasthenia gravis article, very helpful for me..

  2. Very interesting and informative article. I have learned alot, thank you for sharing. Please keep up the good work


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