This post deals mainly with:

• phentermine causing rhabdomyolysis

1. NAME

1.1 Substance

Phentermine

1.2 Group

ATC Classification

Antiobesity preparations, excl., diet products (A08A)
Centrally acting antiobesity products (A08A A)

1.3 Synonyms

Duromine; Ionamin; Linyl;
Lipopill; Mirapront;
Normephentermine; Omnibex;
Wilpo

1.4 Identification numbers

1.4.1 CAS numbers

Phentermine 122-09-8

1.4.2 Other numbers

Phentermine hydrochloride CAS 1197-21-3

Phentermine RTECS/NIOSH SH4025000

RCRA waste number P046

1.5 Main brand names, main trade names

1.6 Main manufacturers, main importers

2. SUMMARY

2.1 Main risks and target organs

Acute central nervous system stimulation, cardiotoxicity
causing tachycardia, arrhythmias, hypertension and
cardiovascular collapse. High risk of dependency and abuse.

2.2 Summary of clinical effects

Cardiovascular - Palpitation, chest pain, tachycardia,
arrhythmias and hypertension are common; cardiovascular
collapse can occur in severe poisoning. Myocardial ischaemia,
infarction and ventricular dysfunction are described.

Central Nervous System (CNS) - Stimulation of CNS, tremor,
restlessness, agitation, insomnia, increased motor activity,
headache, convulsions, coma and hyperreflexia are described.
Stroke and cerebral vasculitis have been observed.

Gastrointestinal - Vomiting, diarrhoea and cramps may occur.
Acute transient ischaemic colitis has occurred with chronic
methamphetamine abuse.

Genitourinary - Increased bladder sphincter tone may cause
dysuria, hesitancy and acute urinary retention. Renal failure
can occur secondary to dehydration or rhabdomyolysis. Renal
ischaemia may be noted.

Dermatologic - Skin is usually pale and diaphoretic, but
mucous membranes appear dry.

Endocrine - Transient hyperthyroxinaemia may be noted.

Metabolism - Increased metabolic and muscular activity may
result in hyperventilation and hyperthermia. Weight loss is
common with chronic use.

Fluid/Electrolyte - Hypo- and hyperkalaemia have been
reported. Dehydration is common.

Musculoskeletal - Fasciculations and rigidity may be noted.
Rhabdomyolysis is an important consequence of severe
amphetamine poisoning.

Psychiatric - Agitation, confusion, mood elevation, increased
wakefulness, talkativeness, irritability and panic attacks
are typical. Chronic abuse can cause delusions and paranoia.
A withdrawal syndrome occurs after abrupt cessation following
chronic use.

2.3 Diagnosis

The diagnosis of acute amphetamine poisoning is made on
the history of exposure or abuse, and the characteristic
features of CNS and cardiovascular stimulation. The presence
of amphetamines in urine or blood can support the diagnosis
but is not helpful in management. Whilst some patients show
signs of toxicity at blood concentrations of 20 µg/L, chronic
abusers of amphetamine have been known to have blood
concentration of up to 3000 µg/L.