Anorexiants (p. 226): Short-term adjuncts to calorie limiting, cognitive-behavioral, weight-loss programs for
severely obese individuals. Nonamphetamine appetite suppressants are commonly used today but are
chemically and pharmacologically related to amphetamines. (Phendimetrazine, Benzphetamine, Diethylpropion
HCl, Phentermine, Lorcaserin)
Precautions and Contraindications: High risk of tolerance and dependence. Should be used in caution with
patients who have a history of alcohol or drug dependence. Use should be limited to 6 months and discontinued
at any sign of tolerance.
Substance Abuse: Patients who abuse substances such as cocaine, phencyclidine, and methamphetamine
should not be prescribed anorexiants because of the potential for excessive adrenergic stimulation.
Alcoholics: Actively drinking alcoholics taking anorexiants have experienced depression, paranoia, and
psychosis.
Diabetes: Patients with diabetes may experiences altered insulin or oral hypoglycemic dosage
requirements.
Lorcaserin: Serotonergic drug. Patients may develop serotonin syndrome or Neuroleptic Malignant
Syndrome like reactions if coadministered with serotonergic drugs. Pregnancy Category X and is not
approved in children under 18.
Anticonvulsants (p. 227):
Hydantoins: First line treatment of choice for tonic-clonic and partial complex seizures and the lease sedating
drugs used to treat seizure disorders of any type. (phenytoin-Dilantin, ethotoin-Peganone, fosphenytoinCerebyx).
Pharmacodynamics: Inhibit and stabilize electrical discharges in the motor cortex of the brain by
affecting the influx of sodium ions into the neuron during depolarization and repolarization, slowing the
propagation and spread of abnormal discharges.
Metabolism and Excretion: Metabolism takes place in the liver and excretion via the kidneys.
Plasma half-lives range from 6-24 hours.
Precautions and Contraindications: Contraindicated under conditions of hypersensitivity. Phenytoin
induced hepatitis is a common hypersensitivity reaction. Other hypersensitivity reactions include fever,
rash, arthralgias, and lymphadenopathy.
Phenytoin: May cause severe cardiovascular events and death has resulted from too-rapid IV
administration. Phenytoin has a Black-Box Warning that IV administration should not exceed
50mg/minute in adults and 1-3 mg/kg/minute in pediatric patients owing to risk of cardiovascular
reactions associated with a too rapid rate of administration. Contraindicated in sinus bradycardia,
sinoatrial block, second-and third-degree AV block, and Stokes-Adams syndrome. Should be
used cautiously in patients with hepatic or renal disease.
Ethotoin: Contraindicated in the presence of hepatic or hematological disorders.
Fetal Defects: Pregnancy Category D. About 10% of babies have defects in Mother’s who take
phenytoin during pregnancy. Newborns exposed to phenytoin is utero may experience decreased
levels of Vitamin K-dependent clotting factors and the mother should receive Vitamin K before
delivery and the newborn at birth.
Adverse Drug Reactions: CNS effects (agitation, ataxia, confusion, dizziness, drowsiness, headache, and
nystagmus), Cardiovascular effects (hypotension, tachycardia, atrial and ventricular conduction
depression, and ventricular fibrillation), GI effects (nausea, vomiting, anorexia, altered taste,
constipation, dry mouth, and gingival hyperplasia), GU effects (urinary retention and reddish-brown
discoloration of urine), Dermatologic reactions (Stevens-Johnson Syndrome and toxic epidermal
necrolysis).
Drug Interactions: Interactions that increase hydantoins effect because of increased metabolism,
competition for binding sites or for unknown reasons occur with benzodiazepines, cimetidine,
disulfiram, TCAs, salicylates, and valproic acid. Interactions that decrease hydantoin’s effect include
barbiturates, rifampin, theophylline, influenza vaccine, pyridoxine, and antacids. Oral contraceptives
effect is decreased with use of hydantoins. Acute alcohol intake may increase phenytoin serum levels,
whereas chronic alcohol use may decrease levels. IV phenytoin should only be mixed with normal
saline.
Monitoring: Patients should be assessed for phenytoin hypersensitivity syndrome (fever, skin rash,
lymphadenopathy), which usually occurs at 3-8 weeks. Baseline CBC, urinalysis, and LFTs should be
assessed prior to onset of treatment, with frequent reassessment during the first few months of treatment.
Plasma levels should be monitored, especially when drugs that increase plasma hydantoin, such as
ibuprofen, are used.
Patient Education: Abrupt withdrawal may lead to status epilepticus. Advise the patient to wear a
medical identification bracelet, to avoid hazardous situations if drowsiness occurs, and to report adverse
effects to the clinician. Patients should avoid alcohol use. Maintain good oral hygiene to prevent
tenderness, bleeding, and gingival hyperplasia. Phenytoin may color the urine red, pink, or reddish
brown but the color change is not a cause for alarm. Advise diabetic patients to monitor blood glucose
levels and report significant changes to the clinician.
Iminostilbenes (p. 235): (Carbamazepine-Tegretol and oxcarbazepine-Trileptal). Structurally related to TCAs.
Used to treat epilepsy, bipolar affective disorder, aggressive and assaultive behavior, and some neuralgias.
Pharmacodynamics: Thought to affect the sodium channels, slowing influx of sodium in the cortical
neurons and slowing the spread of abnormal activity. Carbamazepine exerts its effect by depressing
transmission in the nucleus ventralis anterior of the thalamus. This area is associated with the spread of
seizure discharge.
Metabolism and Excretion: Carbamazepine is metabolized in the liver and has the unique ability
to induce its own metabolism (autoinduction). Due to autoinduction, initial concentrations within
a therapeutic range may later fall despite good compliance. It also induces the metabolism of
many CYP450 enzymes and other substrates. Excretion is through urine and feces.
Oxcarbazepine is metabolized into an active metabolite 10-monohydroxy metabolite, which is
responsible for the pharmacologic effect of the drug. The metabolites of oxcarbazepine are
excreted 95% in urine, 4% in feces, and 1% unmetabolized oxcarbazepine.
Precautions and Contraindications:
Carbamazepine: Contraindications include hypersensitivity to carbamazepine or TCAs, history
of bone marrow suppression, and current administration with MAOIs. Carbamazepine is
Pregnancy Category D; tetratogenic defects have occurred including spina bifida. Black-Box
Warning regarding serious dermatological reactions, particularly among patients of Asian
ethnicity (Stevens-Johnson Syndrome, toxic epidermal necrolysis and risk of developing aplastic
anemia and agranulocytosis). Patients of Asian ethnicity should be screened for presence of the
HLA-B*1502 genetic variant prior to starting carbamazepine. Caution is advised in patients with
a history of previous adverse hematological reactions to any drugs and in those with cardiac,
renal, or hepatic impairment.
Oxcarbazepine: Pregnancy Category C; it crosses the placenta and adverse effects have been
noted in animal studies. Contraindicated with hypersensitivity to oxcarbazepine.
Adverse Drug Reactions: Carbamazepine has a Black Box Warning regarding the development of
Stevens-Johnson Syndrome and toxic epidermal necrolysis in patients of Asian ethnicity.
Carbamazepine has a Black Box Warning due to its potential to cause blood dyscrasias, some potentially
lethal. Carbamazepine can depress the bone marrow and lead to leukopenia, thrombocytopenia,
agranulocytosis, and aplastic anemia. For that reason, a baseline CBC, chemistry, LFTs, and TSH should
be obtained, followed by periodic monitoring. Follow up studies should be more frequent initially,
decreasing to every 3-4 months if the results remain normal. Other adverse reactions to carbamazepine
include hepatic damage and impaired thyroid function. Less serious adverse events include drowsiness,
dizziness, blurred vision, ataxia, nausea, vomiting, dry mouth, diplopia, and headache. The most
common adverse effects observed in patients taking oxcarbazepine were dizziness, diplopia,
somnolence, fatigue, N/V, ataxia, abdominal pain, tremor, and dyspepsia. Hyponatremia may occur,
particularly in the first 3 months of therapy.
Drug Interactions:
Carbamazepine: The interactions of most significance are those that increase the plasma level of
carbamazepine to potentially toxic levels, such as the concurrent administration of
propoxyphene, hydantoins, cimetidine, some Abx (erythromycin, clarithromycin), isoniazid, and
verapamil. Interactions that decrease plasma levels of the other drug occur with beta blockers,
succinimides, valproic acid, warfarin, haloperidol, doxycycline, and nondepolarizing muscle
relaxants. Grapefruit juice increases serum levels and effects of carbamazepine.
Oxcarbazepine: Can inhibit CYP2C19 and induce CYP3A4/5, leading to increased levels of
drugs metabolized by CYP2C19. May decrease effectiveness of contraceptives containing
ethinylestradiol and levonorgestrel.
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