3 - PUVA, NB-UVB and UVA-1 phototherapy Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

UVA wavelength is 320-400nm

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

UVB wavelength is 311nm

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Psoralen plus ultraviolet A (PUVA) photochemotherapy is the photochemical interaction between a psoralen medication and UVA radiation

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Psoralens are naturally occurring compounds acting as natural insecticides

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Human contact with plants containing psoralens and subsequent exposure to sunlight results in phytophotodermatitis

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Phytophotodermatitis represents an acute phototoxic reaction in the skin manifested as erythema, blistering and pigmentation

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The presence of psoralen in the skin before and after exposure can be harmful through unintentional exposure to sunlight resulting in undesirable phototoxicity

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Psoralens are lipophilic and poorly soluble in water

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

There are 2 types of psoralens available, namely 8-MOP (methoxsalen) and 5-MOP (bergapten) where 8-MOP is more water soluble than 5-MOP

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The water solubility of psoralens determines the bioavailability of these compounds

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

8-MOP (Methoxsalen) is available as 2 formulations of dissolved psoralen (Oxsoralen Ultra) and micronised crystals of 8-MOP

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Dissolved psoralen (Oxsoralen Ultra) is rapidly and more completely absorbed as compared to the 8-MOP micronised crystals

A

True (accounts for dissolved psoralen being dosed at 0.4mg/kg and taken 1 hour prior to UVA and micronised crystals 8-MOP being dosed at 0.6mg/kg and 2 hours prior to UVA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

High fat foods can slow down the absorption of psoralens

A

True (psoralens is ideally taken under fasting conditions although food intake can be used to alleviate the nausea associated with high serum level of the drug)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Nausea is associated with high serum levels of psoralen

A

True (food intake with the drug can alleviate this adverse effect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Psoralens exhibit first pass metabolism in the liver and intestines

A

True (therefore doses <20mg may not be clinically effective)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Psoralens highly bind to serum albumin

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

8-MOP (Methoxsalen) is more photoactive than 5-MOP (Bergapten)

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The physical formulation of psoralen influences its absorption

A

True (8-MOP dissolved psoralen more readily absorbed than 8-MOP micronised crystals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Methoxsalen (8-MOP) is completely metabolised in the liver through the CYP 450 system

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Cytochrome P450 inducers have an effect on the metabolism of psoralens

A

True (cytochrome P450 inducers enhance and accelerate the metabolism of 8-MOP therefore reducing the biological effect of PUVA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Most of 8-MOP is excreted in the kidneys

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The peak of the absorption spectrum for psoralen molecules to be activated to the excited singlet state is in the region of 320-330nm

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

PUVA therapy suppresses DNA synthesis through the formation of monoadducts and cross links in the DNA

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

PUVA therapy causes selective immunosuppression

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

NB-UVB phototherapy is almost as effective as PUVA for psoriasis not involving the palms and soles

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

NB-UVB has replaced PUVA as the treatment of choice for vitiligo as both treatments have comparable efficacy but NB-UVB is simpler

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Vitiligo on the face and torso are more responsive to phototherapy than on the limbs

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The eczematous and plaque stages of mycosis fungoides respond to PUVA

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The tumour stage of mycosis fungoides does not usually respond to PUVA

A

True (PUVA is usually not effective in the tumour phase of the disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Sezary syndrome is not responsive to PUVA

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Patients with various photodermatoses can be desensitised by prophylactic exposure to a brief course of PUVA

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Pemphigoid is contraindicated in PUVA and NB-UVB

A

True

33
Q

Pemphigus is contraindicated in PUVA and NB-UVB

A

True

34
Q

Lactation is contraindicated in PUVA

A

True (because psoralens is probably secreted in breast milk)

35
Q

Lupus erythematosus with photosensitivity is contraindicated in PUVA and NB-UVB

A

True

36
Q

Xeroderma pigmentosum is contraindicated in PUVA and NB-UVB

A

True

37
Q

A 25% reduction in PUVA dose should be considered in patients taking photosensitising agents

A

True

38
Q

PUVA dose should be readjusted when patient is concurrently on doxycycline

A

True (photosensitising agent)

39
Q

PUVA dose should be readjusted when patient is concurrently on fluoroquinolones

A

True (lomefloxacin and sparfloxacin are photosensitising agents)

40
Q

The PUVA radiation dose is dependant on skin phototype

A

True

41
Q

If widespread erythema is present post PUVA, treatment should be stopped until the erythema clears

A

True

42
Q

When >95% of the psoriasis area has cleared post PUVA, the patient is stepped down to a maintenance schedule of PUVA

A

True

43
Q

If a significant (>5%) amount of psoriasis begins to return then the frequency of PUVA can be increased or stepped up to a clearance schedule

A

True

44
Q

Areas shielded from PUVA therapy should be concurrently managed with topical corticosteroid therapy

A

True

45
Q

Eye protection with UVA blocking glasses is required for PUVA therapy

A

True (required from time of psoralen ingestion until sunset that day when the patient is exposed to sunlight)

46
Q

A sunscreen with at least SPF 15 ideally includes avobenzone as an ingredient is advised for photoprotection from psoralen phototoxic reaction

A

True

47
Q

Nausea correlates with the serum level of psoralen

A

True (most common adverse effect)

48
Q

The PUVA itch (pruritus) and subacute phototoxicity are indications for stopping treatment until they clear

A

True

49
Q

Symptomatic erythema is the most common phototoxic reaction

A

True (10% of patients)

50
Q

PUVA may cause CNS disturbances

A

True

51
Q

PUVA may cause depression

A

True

52
Q

PUVA may cause headaches

A

True

53
Q

PUVA may cause hyperactivity

A

True

54
Q

PUVA lentigines is an association of PUVA treatment

A

True

55
Q

NMSC incidence is markedly increased in patients who receive high cumulative UVA exposure

A

True (dose dependant)

56
Q

The SCC is PUVA patients are not biologically more aggressive than actinically induced SCCs in immunocompetent patients

A

True

57
Q

There is an increased risk of SCC on male genitalia with PUVA treatment

A

True

58
Q

PUVA may cause herpes simplex virus recurrences

A

True

59
Q

There is no increased incidence of cataracts with PUVA

A

True

60
Q

Thiazides diuretics do not cause acute phototoxic erythema with PUVA

A

True (though a potentially photoactive agent, thiazides diuretics do not cause phototoxicity with PUVA)

61
Q

Carbamazepine may reduce the effectiveness of PUVA

A

True (carbamazepine is a CYP 450 enzyme inducer and enhances the metabolism of psoralen)

62
Q

Phenytoin may reduce the effectiveness of PUVA

A

True (phenytoin is a CYP 450 enzyme inducer and enhances the metabolism of psoralen)

63
Q

Other CYP 450 inducers may reduce the effectiveness of PUVA

A

True (enhance the metabolism of psoralen)

64
Q

Skin cancer is the most important adverse effect of long term PUVA treatment

A

True (need for long term skin checks even after cessation of PUVA)

65
Q

The peak of the action spectrum for phototherapy of psoriasis is in the 320-340nm spectrum

A

True

66
Q

UVB is absorbed in the epidermis and papillary dermis

A

True

67
Q

UVA wavelengths generally penetrate to the mid dermis

A

True

68
Q

Topical emollients are advised before NB-UVB to make lesions more transparent

A

True

69
Q

Bullae may appear on psoriatic plaques after NB-UVB phototherapy

A

True

70
Q

Lupus erythematosus may be a consequence of NB-UVB treatment

A

True

71
Q

Pemphigus may be a consequence of NB-UVB treatment

A

True

72
Q

Pemphigoid may be a consequence of NB-UVB treatment

A

True

73
Q

Recurrent herpes labialis may be an adverse effect of NB-UVB treatment

A

True

74
Q

Polymorphous light eruption can be an adverse effect of NB-UVB treatment

A

True

75
Q

UVA-1 wavelength is 340-400nm

A

True

76
Q

UVA-1 treatment is equivalent to NB-UVB and UVA treatment

A

True (no clear advantage of UVA-1)

77
Q

UVA-1 produces DNA damage in vivo and in vitro

A

True

78
Q

Erythema is the main short term effect of UVA-1 phototherapy

A

True

79
Q

Erythema from UVA-1 phototherapy is usually asymptomatic

A

True (usually asymptomatic and does not interfere with treatment)